Of course, his personal survival roll ought to be rediculously easy in areas with lots of vegitation - it's just organic matter, no listed need for a particular type.
If survival rolls aren't desireable (due to the low-speed travel, perhaps, or a desert environment), then pick up lots of feed. At 5 cp/10 lbs, a 150 lb ooze costs 75 cp, or 7.5 sp, or .75 gp per day to feed.
Firewood might also suffice, at 1 cp per 20 lbs, for 8 cp to feed a 150 lb half-ooze each day.
Compare to trail rations at 5 sp/day/person.
Weight could very easily be an issue, however, so you will want to pick up a heavy horse (200 gp each) or two and a cart (15 gp) or wagon (35 gp) and some ranks in Handle Animal to deal with the weight. Portable Holes (20,000 gp) are also a good idea, if a tad pricy (no listed weight limit, but a volume limit).
Of course, while actively adventuring, you can devour fallen opponents. Hmm... can you devour live opponents that way? Scary attack, that.