I wouldn’t worry overly about the accessories. In the current market you’ll have to take what’s available. Most accessories aren’t hard to remove if desired. For example, a standard roof vent fits in the same opening as the roof A/C. But you may find many of them are pretty nice to have. 2500# is doable. I’d go with a single LP tank to reduce weight
on your hitch, but that’s not hard to convert.
Renting is a great idea. Have you located a place that rents them? There aren’t many that I know of, and others might be interested.