Every system you try will have flaws, or you may salivate over a feature that appears in other software.Some familiar names are mentioned frequently: Stessa, Apartments.com, RentRedi, TenantCloud, Innago, RentManager, Avail, Rentec Direct, Doorloop, etc.I recommend conducting thorough research on each app online to understand their offerings, pricing, etc.

If so, make sure agreement is in writing, signed by both parties, specifies new end date and ensures any existing security deposit will still be dealt with properly per landlord/tenant laws, and I'd also ask for a partial payment to be issued at signing to make obtaining his new place easier.  

Since you are doing shorter term deals it appears, you may want to get creative with the accounting and structure to maximize profits.

It appears that a significant portion of the business's value lies in its name, website, marketing, furnishings and other intangible assets.

Start with an easier and more realistic project.

So for a good deal flow you need to market, your farm needs to be several thousand units large.Frankly, it's a lot easier to become an agent.To that regard I’ve seen a real estate agent spend half of what it would have taken to built a profitable wholesaling business and become THE dominate agent in our city of 135,000 people.  

I have started using a spreadsheet but I would like something that makes it easier to keep track of when I have sent the owners a letter or postcard etc; also to attach a picture of the property and some pdf's of county record documents.

@Shango Collier the sellers would need to speak with a lender regarding what proof would be needed to "ignore" the payment on a property where someone else is making the payment.Or it, might be easier to convince a lender to treat the Land Contract like a lease, so 75% of the income could be used to offset the PITI.

It will likely be more difficult to rent to a able-bodied tenants and much easier to rent to disabled tenants, possibly at a premium since it is (almost) ready to go.

Their coaching program pricing appears to be reasonable compared to other programs, that lures you in then upsells participants to their 50-60K packages.