I'd separate the jumping its just going to confuse the issue and has the potential to make you look unreasonable.

You can borrow from a lender and have a pref equity investor with a hurdle of 8-9 percent and then a cap on proceeds when you sell property.

You have to know your end strategy, MH by themselves aren't as liquid, have financing hurdles, what kind of shape it will be in , can you get someone to move it, how much will it cost. 

The upside of course is when you clear all the hurdles its guaranteed rent on the 1st of every month and that's a BIG plus in some areas where getting the rent on time and in full is like pulling teeth. 

If not, you have a problem as your listing agreement would only be for 50% of the land (or some other percentage if stated in the deed).If you can get past that hurdle, whether your contract is enforceable at this juncture would depend upon whether it is binding on seller's heirs, personal representatives, successors, etc. 

It doesn't sound too unreasonable to me.

If the owner offers seller financing at an unreasonable price, the REFI math at 70% LTV best you can get for commercial deals, with no experience 1st time buyer, math shows you CANT REFI out without adding an impossible amount of NOI increases in a time frame that isn't possible.  

We have the 20% cash, but now we are jumping over the financing hurdles.

While doing that, I faced some hurdles around getting accurate economic, demographic, and real estate market data that didn't require a big software subscription and was also hyper local.

If not, you were only over ~23-24% (@130k), which is a bit high, but not unreasonable and fairly close to the typical 20% contingency for all but the most experienced.