I measured yesterday. From the back bumper to the front is ~25', but with the front mirrors (which I intend to keep) it's ~26'. I plan to add a small motorcycle rack on the back of mine, bringing the total length to ~28'
This looks great. You're gonna have so much fun working on this thing, all the things you're learning now will be super useful later in life and will put you a few "practical" steps ahead of a lot of college students.
Do you have a full plan for the interior? Are you going to have a heater/AC? Bathroom? Water plan? Just like installing the roof items before putting a ceiling in, it's probably useful to install all the undercarriage items before putting in a floor.
26' feet is a common max length for Rv camping slots in National and most State parks. Over that and you drop down to 75% accommodations. Also your agility and practical parking increases dramatically for every foot over 25". I've seen many people that remodel a big bus and become disenchanted with the sheer size and weight of it. A big bus definitely has is awesome potential. Traveling boondocking and agility ....Go SMALL!