Land/Home Development Question

I have 15 2.5 acre home sites that my family purchased years ago in 40 acre +/- tract of land(lots already platted). It is in a desirable rural area in Alabama with good school systems. We have enjoyed it as a family farm for years. Nice pond, trails etc… It is no longer being used and I am ready to develop it. I will preface that I have owned a 22 pad park for 5 years. 10 of those homes I have purchased and moved in to my park. The land is paid for. Land is probably worth $150,000 as is. I am in a position to carry the paper on early to mid 90’s mobiles(Moved in for 12K or so). I will have to install septic, do some road work, etc… Have any of you developed a piece of property like this for Land/Home? Please provide some input. Have you had luck in getting the homes financed by 3rd party lenders? What expenses am I leaving out? We currently have a 16 x 80 early 90’s home on one site and it tax appraises for $34,700. We do not have it rented. Just a family get away that never gets used!!! Input is appreciated as always. I am in commercial brokerage and ownership and think you guys are the best source for information regarding MHP ownership in the business. I will start contributing more when appropriate.