I kept getting credit card offers (almost daily) for 0% interest for 12-15 months.

I checked the credit card that I gave the lender to pay for the appraisal and I've been charged $685!

I have good credit, sufficient savings and it's a great property!

Not legal advice, but I would Hope that your contract for carrying the financing is contingent upon a "satisfactory" review of the buyer's financials, credit, etc.See an attorney ASAP.

My credit is where it needs to be, but the financing is definitely the area that concerns me the most.

My opinion on the best way to measure this is my running your numbers on the property and decide if you're happy with the cash-flow and rates of return.Chris Clothier is right about the creditability of the provider you're working with, as well as the rest of their team.

you'll get differing responses as lenders have differing policies on bonus' how its structured, down payments line of work etc when they calculate your DTI.no idea if your going FHA or conventional either - best way to do it is just go to your local branch credit union and give them your info.

If house appraises for 50k, would a 40k line of credit be reasonable ?!

After going through the crash as a full-time investor, I'm not sure that I want to be there again unless/until I have a much better base of operations (positive cash-flow properties and PLENTY of cash and/or lines of credit to weather a storm).

Not all land contracts allow early payoff.Your equity position coupled with halfway decent credit, I hope, should be enough to qualify you for a loan.