Hills are a non-issue with the shorter gas engined A's. The V10 has 360hp and 450 lb-ft of torque and if you're 33-34ft and under will be moving a 20,000 lb coach. Any DP will be 10,000 lbs heavier with the same hp, a bit more torque (600 lb-ft range) but won't be any faster. You will get the benefit of not as much power loss in the really high elevations (7000 ft+) with diesel because of the turbocharger. I live in a valley at 2500 ft and to get in or out the rig must climb to at least 4000 ft. The slowest is 50 mph on the steepest part coming from the south into the valley which is a long climb (~20 miles all uphill). The rest of the time I'm at 65 mph easily. With the exception of that one part, conversations are easily had. No yelling and screaming but based on reports from other gas MH owners, it seems sound insulation is not all equal. Test different coaches.
About auto levelers, ease of setup was THE main reason we switched to a MH.
EDIT: Some of the newer gas class A's have a power front bunk that sleeps two easily. Some of the Thor gas MH's have that feature but I've seen some others.