I ran 33s with a 2.6, a bad carb, and at high altitude (no lower that 5,280 feet) for almost a year. It definitely sucked on the highway but they were great on the trail.

Since then I've got a good carb and I've re-geared to 5.29 diff gears. Runs great on the highway now and hills are no problem. I can stay in 5th gear on most hills and can accelerate in 4th. Even on the approach to Eisenhower tunnel - which is a 7% grade over 11,000 feet - I can climb that in 3rd gear and it's not much trouble.

I'm considering moving up to 35s when my current set of 33s wears out.

If you keep the stock gearing and just simply ensure you have a good running carb you should still be able to get around okay on 33s.