4.6.5 -> 4.7.5 incremental upgrade, breaks at 4.7.0

I have a client site running version 4.6.5. I need to upgrade their Drupal install to make use of some new modules that do not work with their current version. I would like to upgrade to 4.7.5.

I tried going directly from 4.6.5 to 4.7.5 but that produced a large list of SQL errors and failed upgrade messages.

I restored the database and php files from backups.

I then tried going from 4.6.5 to 4.6.11. That seemed to work. I then tried upgrading from 4.6.11 to 4.7.5 but that produced a large list of SQL errors and failed upgrade messages.

Again I restored the database and php files from backups.

I then tried upgrading to each individual revision step by step, all the way from 4.6.5 to 4.7.5. When I get to the 4.6.11 to 4.7.0 upgrade I get a large list of SQL errors and failed upgrade messages:

* user warning: Table 'search_total' already exists query: CREATE TABLE search_total ( word varchar(50) NOT NULL default '', count int(10) unsigned default NULL, PRIMARY KEY word (word) ) in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Can't DROP 'path'; check that column/key exists query: ALTER TABLE blocks DROP path in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Duplicate column name 'visibility' query: ALTER TABLE blocks ADD visibility tinyint(1) NOT NULL in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Duplicate column name 'pages' query: ALTER TABLE blocks ADD pages text NOT NULL in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Multiple primary key defined query: ALTER TABLE sessions ADD PRIMARY KEY sid (sid) in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Table 'flood' already exists query: CREATE TABLE flood ( event varchar(64) NOT NULL default '', hostname varchar(128) NOT NULL default '', timestamp int(11) NOT NULL default '0' ); in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Duplicate column name 'aid' query: ALTER TABLE accesslog ADD aid int(10) NOT NULL auto_increment, ADD PRIMARY KEY (aid) in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Table 'queue' already exists query: CREATE TABLE queue ( nid int(10) unsigned NOT NULL, uid int(10) unsigned NOT NULL, vote int(3) NOT NULL default '0', PRIMARY KEY (nid, uid) ) in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Unknown column 'votes' in 'field list' query: SELECT nid, votes, score, users FROM node in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Can't DROP 'votes'; check that column/key exists query: ALTER TABLE node DROP votes in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Can't DROP 'score'; check that column/key exists query: ALTER TABLE node DROP score in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Can't DROP 'users'; check that column/key exists query: ALTER TABLE node DROP users in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Table 'vocabulary_node_types' already exists query: CREATE TABLE vocabulary_node_types ( vid int(10) NOT NULL default '0', type varchar(16) NOT NULL default '', PRIMARY KEY (vid, type)) in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Unknown column 'nodes' in 'field list' query: SELECT vid, nodes FROM vocabulary in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Can't DROP 'nodes'; check that column/key exists query: ALTER TABLE vocabulary DROP nodes in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Unknown table 'page' query: DROP TABLE page in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Duplicate column name 'types' query: ALTER TABLE blocks ADD types text in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Duplicate column name 'module' query: ALTER TABLE vocabulary ADD module varchar(255) NOT NULL default '' in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Unknown column 'voters' in 'poll' query: ALTER TABLE poll CHANGE voters polled longtext in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.
* user warning: Multiple primary key defined query: ALTER TABLE term_node ADD PRIMARY KEY (tid,nid) in /home/greg/dev/drupal/includes/database.mysql.inc on line 120.

And I get a bunch of failed upgrade messages:

The following queries were executed
system module
Update #110

* DROP TABLE {search_index}
* CREATE TABLE {search_index} ( word varchar(50) NOT NULL default '', sid int(10) unsigned NOT NULL default '0', type varchar(16) default NULL, fromsid int(10) unsigned NOT NULL default '0', fromtype varchar(16) default NULL, score int(10) unsigned default NULL, KEY sid (sid), KEY fromsid (fromsid), KEY word (word) )
* Failed: CREATE TABLE {search_total} ( word varchar(50) NOT NULL default '', count int(10) unsigned default NULL, PRIMARY KEY word (word) )
* Failed: ALTER TABLE {blocks} DROP path
* Failed: ALTER TABLE {blocks} ADD visibility tinyint(1) NOT NULL
* Failed: ALTER TABLE {blocks} ADD pages text NOT NULL
* DELETE FROM {variable} WHERE name = 'node_cron_last'
* UPDATE {blocks} SET status = 1, custom = 2 WHERE status = 0 AND custom = 1

Update #111

* DELETE FROM {variable} WHERE name LIKE 'throttle_%'
* Failed: ALTER TABLE {sessions} ADD PRIMARY KEY sid (sid)

Update #112

* Failed: CREATE TABLE {flood} ( event varchar(64) NOT NULL default '', hostname varchar(128) NOT NULL default '', timestamp int(11) NOT NULL default '0' );

Update #113

* Failed: ALTER TABLE {accesslog} ADD aid int(10) NOT NULL auto_increment, ADD PRIMARY KEY (aid)

Update #114

* Failed: CREATE TABLE {queue} ( nid int(10) unsigned NOT NULL, uid int(10) unsigned NOT NULL, vote int(3) NOT NULL default '0', PRIMARY KEY (nid, uid) )
* Failed: ALTER TABLE {node} DROP votes
* Failed: ALTER TABLE {node} DROP score
* Failed: ALTER TABLE {node} DROP users

Update #115

* No queries

Update #116

* DELETE FROM {system} WHERE name = 'admin'

Update #117

* Failed: CREATE TABLE {vocabulary_node_types} ( vid int(10) NOT NULL default '0', type varchar(16) NOT NULL default '', PRIMARY KEY (vid, type))

Update #118

* Failed: ALTER TABLE {vocabulary} DROP nodes

Update #119

* No queries

Update #120

* No queries

Update #121

* Failed: DROP TABLE {page}

Update #122

* Failed: ALTER TABLE {blocks} ADD types text

Update #123

* Failed: ALTER TABLE {vocabulary} ADD module varchar(255) NOT NULL default ''
* UPDATE {vocabulary} SET module = 'taxonomy'
* UPDATE {vocabulary} SET module = 'forum' WHERE vid = 2

Nothing after Upgrade #123 contains any failed messages so I did not include it.

I've wasted nearly half a day and didn't even get the site upgraded. Where do I go from here?