Complex question here.... Whats the market occupancy at ? Wheres your heart at? Do you have an obligation to investors? What is your strategy flip /hold?.
If the mkt is strong and parks full with mkt at 300, could you raise the rents 150, i would think you could.
Are you going to make improvements to the park? Or just jack the rents?
Are there legalities in your state on an increase/the amount?
Do you have any concern as doubling rent on the property?
I personally don't think short term financing is good idea. It would be best to place in longer term debt if possible. If you can get short term seller carry, see if you can get longer term ( maybe provisioned extensions with lump sum principal payments on an extension if needed -believe this is franks tip)
@erikhanson probably has some good advice on a bank appraisal when lot rents are really low and how that might be factored into the valuation. I think i remember this from a podcast or the forum here if you cant do seller carry.
Do you have investors that you have to answer to and maybe explain why your rents are artificially low if you put them on tiered rent increase schedule to get to market?
Those are some points to consider. I think there is an array of ways that different operators would answer this question so wont answer it personally but give you some variables to consider when weighing the options.