You have to work out what is your own preference.
A 30 foot C and a 30 foot A gasser usually have the same footprint (most are built to the same width), but the A will have more usable floor space when parked. If you choose the right model level, the A will have a higher floor, higher profile, and more outside storage under the floor. It will usually have larger tanks.
I know two reasons to prefer a C:
1. You want the finished cab of a van, with the extra doors and a front end built to passenger vehicle crash safety standards, and climate control sized for the space.
2. The over-cab space is useful to you, either as a sleeping space for yourself or guests, or as temporary storage when not moving. Small A's can be fitted with a drop-down bunk for equivalent sleeping space, a standard feature when all motorhomes were A's and were typically 17-28 feet long, and coming back now as an option in the 22-32 foot range.
There is not much difference in chassis service, A gasser or C. The smallest A's are built on a stripped van chassis, more a less a C without a cab. But around 30 feet or so, they get built on a bare chassis with 2000-4000 pound more capacity than the heaviest E-series (or going further back, GM G-series). Regular service points are reached under the hood or from underneath, in both cases, and either one requires that you find a truck service center for chassis work.
There is really no difference taking care of the house, which is where most of the work will be. Appliances, construction methods, points of maintenance are pretty much the same. One possible difference, some larger A's will have water tanks in an enclosed space between the floor and the chassis, where they should be well protected from hazards but almost impossible to reach once the shell is built and enclosed.
I'm another who prefers no slides, hard to find in a new motorhome today. I have two slides, which fit the needs of my wife, children and grandchildren for lots of floorspace, but also made this particular RV less usable with slides in.
If you are willing to consider 30 feet, you might also consider up to about 32 in an A gasser. This is the size at which you get sofa, dinette, lounge chair space, and work space in the kitchen, in the 1980s and 1990s floor plans. For what you think you want to do, I recommend you look at Flair, Southwind Storm, and Bounder (all from Fleetwood) of this era, but you will find similar floorplans in Tiffin's Allegro, Winnebago Brave and Adventurer, Coachmen Mirada and Santara, FourWinds Hurricane and Windsport, Damon Daybreak and Intruder, as well as assorted models from Georgie Boy, National, and Forest River. Not all of these will have the basement space, rather some will have lower floors and smaller outside bins.
Look at PPL motorhomes (an easy search) for examples of what can be found in this size in the 1990s, layouts and prices. It would be quite reasonable to expect to find a livable A gasser motorhome from the 1990s, no slide, this size range, for $8000 to $15,000. Not necessarily low mileage, but you are not planning to put big mileage on the thing.
In your price range, I'd be looking for something like this
Fleetwood Southwind or
Winnebago Brave.I'm not so sure living in a motorhome is going to be less expensive than living in a mobile home or a small flat, even if you try to live off the grid in an urban area. But I'm used to living in a low-rent part of the country, the cost of living situation in the West might favor RV economics more.
