The first part of all the ideas is to figure out exactly what a years worth of expenses for the van costs minus gas. It sound like this is already mostly done. Factor in the price that was paid for the van and a percentage above that to cover incurred costs etc (we may have to spread this over a year or two depending on the figure and load)
For instance, insurance is 400$ a year, the tires look balding so new ones are needed this year at a cost of 200$ and we still owe the original buyer 1000$..thats a yearly upkeep of 1600$.
Idea one the PTP Van-Share
We start a PTP Van Share Pool. Members of the PTP can elect to cover a percentage of the vans yearly costs. Those members then split the use of the van over the year in proportion to their coverage.
From the collected sum the insurance is paid, the original owner is paid, upkeep on the van is paid and the rest goes into the PTP pool of funds with a notation of how much and from whom.
Two members pony up 400$ each, one member hold a fund raiser and collected 200$ and two others come up with 300$.
Member 1 400 25% 91.25 days of use Member 2 400 25% 91.25 days of use Member 3 200 12.5% 45.63 days of use Member 4 300 18.75% 68.44 days of use Member 5 300 18.75% 68.44 days of use This gets a little problematic on the bookkeeping end, but it is doable so long as all involved are amicable and learn to use a web based tracker system (of which I have about a dozen we can set up and use)
Idea two Redeemable Options
Another way is to take the yearly cost and break it down into a per day cost. This would give us the value of a One Day Use option certificate. These get sold in 1,10 and 30 denominations. In the example of 1600 yearly cost that would be 4.38$ a day.
For instance, I want to run a few PublicDomainBookKiosk events at various schools. I would figure how many days I would need the van, pad it up to cover set up, pick up, drop off and maybe a few extra just toss some good karma into the whole thing. Let say I would need it for two 10 day blocks and 3 one day blocks, thats 23 Options @ 4.39$ an option or 100.82$
Once I have purchased an Option I use the handy dandy web interface to book time, which is first come first served. Blocks are reserved as just that, a block of contiguous days. Single days are just that , single days.
Some folks will want blocks, some will want single days. Those folks buying options simply to be philanthropic should buy in single days.
Idea three Stationary Usage
Even if the van is not drivable, could it not be park somewhere to be a kind of Base Station/Mast/AP/Ubernode? All the gear in it is still usable other than the thing as a whole is not mobile.