The deal you seek exists but it would take a lot of time resources, effort and energy to find. Luck is also helpful.
You have 35k which is not a lot . That being said , we have done deals with less money. Realistically, a lot of sellers even on seller carry may want 20-25% . The lowest one I had under contract was for 9.9% but you were going to need money and strong nerves (fell apart due to some other issues).
I have a deal we are working on that fits the bill of what you are looking for that we would hopefully get under contract. Has been a couple years in the making . Except the appx 35 k translates to a 25% down payment. It is not generating any 1500 positive cash day one ( you are essentially looking for 50% cash on cash day 1 and you need to create those deals). This deal we would probably be buying at a 9-10 cap on actuals but the rents are not quite half of market.
So as I said your deal exists but its going to be really rough to find just like that. Some other things you might consider. Realistically , you are wanting an extremely high CoC return. Again, possible but most people would not recognize them. If you start looking at value add deals with potential for upside and refinance, resale (liquidity event) , you would be more probable to get the high returns you are going for.
Ie buy a 100k park for 20k down then jump the park value and sell after the second year for 140k. That is probably going to be more realistic with a low budget if you try and figure out how to grow your capital base.
Some other things you can think about, you only have 35k but maybe you can find a good deal and find a partner for it. Perhaps this deal requires 80 k down. You can put in your 35k ( and then since you also had the deal maybe that adds a little value and they contribute the balance. Remember, half of a good deal is better than all of a crappy deal.
Aside from that, know how you are going to operate the deal because its going to be a smaller park if you aren't willing to look out of the box.