You will be looking for an investor who has a lot of experience with sub2 and also deeper pockets. $60k s a substantial amount of cash for anyone to leave into the deal. Just because it's a sub2 with a better interest rate, most investors are looking for a rate of return. With $60k and the fact that your UPB is now $250k they are going to weigh up if it's worth it. If you can get in and out of a BRRRR let's say leaving $10k in the deal.
Obviously not having your name tied to the debt is a plus, but also if you haven't structured these correctly they can come back and bite the investors (due on sale, issues with prior owner of record etc).
To me the rental spread is great, the OOP is high and the equity is lower than I would want for that type of capital input. If s*** hits the fan, i would want to easily be able to refinance out of it, let's say 70% so needs some equity in it OR i am just having to bring even more cash to the table to get it done.
Further, don't assume the $50k in arrears get's applied to the UPB. a Large majority of that is fees, trustee costs etc. so even with $50k + your $10k fee - the UPB needle isn't going to shift much. If you had to refinance, your still going to be bringing a lot more cash into the deal.
Lastly - this is a rural and underserved area. I quickly ran it through the tool most commercial brokers are using (consumer finance). When i saw the population, i thought you would struggle to get it rented quickly if necessary. This is another factor that some of your buyers would consider - not to knock your deal, this is just my insight. I hope you get it sold!!!