Hi Dave and Tammy,
Significant-downsizing is always a major adjustment. You will compromise in every category from a physical perspective. But as you are hoping for, going small and more simplistic has all it's own advantages. Considering a 25 foot Sprinter-based rig is going quite small. The good news is that many small floor plans are offered. Your biggest compromise will be sleeping arrangements. If you must sleep together in a walk-around bed, then there are just a few available floor plans to choose from. They come in a rear slide-out or side slide-out Going a bit longer than a Sprinter can offer, say around 26 feet, I think you will find more choices, especially if sleeping separately, each in your own single bed.
I am partial to the Phoenix Cruiser brand we have for the price/quality ratio, the rig we have
HERE, owned since 2007. I am also fond of the capability/cost/maintenance ratio the E-series has which gets some criticisms over confinement and noise at high rpm. Be sure to compare all the pros to the cons between chassis choices and the unique benefits of each fuel type, gasoline and diesel. As you noticed, a Sprinter diesel typically is outfitted with a propane generator. Another Sprinter deficiency is idling for hours at a time has severe consequences. Then adding the cost of Sprinter maintenance and limited service centers. But the Sprinter is more tamed and comfortable.
CLICK HERE to look at all the various Phoenix Cruiser floor plans, many less than 26 feet. Model 2351D offers a double bed in a slideout. I feel the over-all length of 24'-11" is a whole lot of "capable" motor home in as small of a package possible without sacrificing anything. Phoenix offers optional auto-levelers and much much more.