First Dabble with Creative Financing, a bit lost

[Sean H.]

I have a commercial property lined up that is a good deal.

List Price: $500,000

Tenant 1: Doctor, been there for 4 years, very happy in current location will renew lease in spring, paying $33280/yr.

Tenant 2: Doctor, been there for 1.5 years, very happy in current location, plans to renew lease in 3.5 years. Paying $47840 / yr.

Taxes: $14396 / yr
Ins quote: $1485 / yr
Landlord responsible for water/sewer, past 12 months average $400/mo for both. $4800 per year.
Property was built in 2006. No maintenance issues.

NOI: $60439.

Even with 100% financing, 500k 20 yrs at 6%, it will cash flow about $17500 per year.

Here is where I break down. The owner will hold 25% paper. My lender will lend up to 75% of purchase price. 75+25=100% wooo!!! I'm done right?? I do not think it is that simple, but I feel like I have a flexible seller and a good deal on my hands. Would like to try to make it work creatively. Are more details needed?