What is a home? A home contains the following (with RV specific functions in parentheses):
I wouldn't move a lot. I could stay in one place for a week or a few months. The point is the ability to take your home with you and live wherever you want.
A motorhome or a trailer? I don't see the point of a separate car or tow vehicle. If I need to drive to the city, I usually stay in the city for a few days, so may as well take my home with me.
For nimble mobility I could have a motorcycle, or an electric bicycle/motorcycle. The motorcycle can be stored within the motorhome in a mini-garage.
What you give up is having a big open space, and private spaces when having guests.
Apart from satisfying all the needs listed above, specifically the following:
Class C because the only thing I need a bed for is sleeping, and what better to have underneath the bed than seating, with swiveling captain chairs. It may be possible to sit upright in a tall overcab bed. Positive points on goodsam forum, reddit vandwellers 1, reddit vandwellers 2, and reddit vanlife.
Behind the front seats, modularity should be a design goal so that the space inside the home can be organized as needed. The walls and floors could have adjustable connection points for any module such as storage, tables, sofa-bed, etc.
A retractable table behind the swivel captain chairs, along with a sofa makes for a good office/dining area. A computer screen can fold down from the ceiling, rotate 360, and even swivel to the wall. The sofa converts to a bed for guests.
Even overhead storage could be modular. What kind of securement would allow quick release and gliding along the ceiling? The walkway can change based on where the overhead storage is placed. Just an idea. Maybe a central walkway is fine.
As for the rest of the storage along the open floor, stackable plastic tubs and plastic furniture with drawers are lightweight and cheap. They can be placed on crates with lockable wheels so they can easily be moved around the interior. A work van motif.
Worktable sections fold out from the wall, and the storage tubs or drawers can be moved underneath the worktables if desired.
The kitchen, bathroom, and laundry probably benefits from being stationary due to water and other connections.
Maybe the entire left side of the motorhome could expand to add space. The back storage area walkway could magically appear when the motorhome wall expands. Although the overhead storage on the left side may be a challenge to move with the expanding wall. Not sure.
So with the expanding wall on the left, the kitchen, laundry and bathroom are on the right? Not sure what the design constraints are for an expanding wall.
Can an outdoor area be added to the living space with a tent? For example , you're cooking outside but want protection from mosquitoes. Can a tent magically form by itself with the push of a button?
With the expanding section, I could easily fit everything into a 19-22 foot class C motorhome. Including a parking spot for a motorcycle.
Ideas that I've discarded:
In the bathroom, the pee could be diverted to go outside via hose instead of a pee tank (as an option). Although that may not be possible with a modular toilet. Based on Every Toilet for Vanlife - Reviewed! by Ready.Set.Van 2024, the Ogo Composting is a good design. Less expensive would be the Luggable Loo. Also see Toilet Showdown for Vanlife by Ready.Set.Van 2022.
A wet/dry shower as designed in the Winnebago Ekko, where a wall pivots to close the sink over the toilet and reveals the shower.
Do I need an RV washer dryer or can a small full-power front load washer be used? Regardless, I always run the washer at 30C max and the dryer low heat to save energy.
A kitchen section that can be swiveled or moved outside so on hot days the heat from cooking doesn't add heat to the interior. Maybe not worth the complexity. I don't cook much. I can cook meat in large quantities, and store in a frige/freezer. Alternatively, individual cooking appliances can be moved outside. A large toaster oven is lightweight. An electric range is lightweight. An outdoor pulldown table is all that's needed.
Maybe I don't want to carry that much water, as it's heavy. With heating lamps surrounding me from all sides I may not need to run the water continuously to feel warm. The heating lamps will use less energy than heating water.
Smallish grey water tank to take up little space since that can be dumped most anywhere. Optional hose running from shower floor to outside instead of going to grey water tank with pump.
Battery for solar also hooked to engine where the alternator is a backup for solar charging. Probably don't need an additional alternator, but it's an idea.
Better would be if the motorhome was purely an EV. In which case use butane for heating water, electric for everything else. However, EV homes aren't available, and finding an inexpensive used class C and remodeling it would make more sense. Although you could remodel a used EV sprinter van if I could find a way to add an overcab bed.
A large array of solar panels unfold and tilt to increase solar power and to provide shade for the vehicle as an awning. For example, Stella Vita. For Example Solarolla.
Plumbing should be freeze resistant.
Something to easily set up clothes lines to dry clothes outside when advantageous to do so.
Air quality sensors.
To simplify by not adding an additional system, use the air conditioner that's powered by the motorhome's engine. I don't mind having a redundant heat source like a butane canister because it is simple, compact, and low cost, but since running the engine would complement charging the batteries and heating water for a shower, it's not a waste to be running the motorhome engine instead of a generator.
Likewise an interesting idea I probably wouldn't implement is a wood stove.
LUXURY 144 4x4 Sprinter by Nikki Delventhal on YouTube.
I like the foldout shower idea for saving space. Falls into the modularity of space theme. Huge battery bank is probably a good idea.