I perhaps naively went ahead with the registration and inspection after completing purchase of the home, and wound up with a hefty repairs bill of around 3k.

Looking back 7-8 years from when I did that, if I had held on to the one property between cash flow and appreciation, I'm not sure I'd be any further ahead. 

We try to get ahead of the issue by preventing it in the first place.

Set aside reserves for unexpected repairs or vacancies.

Analyze potential deals by estimating the After Repair Value (ARV), repair costs, and total expenses. 

If you can rent 3 units for $2,000 you are close to breakeven.On the plus side, you will have a highly attractive asset and several decades without much cost of capex and repairs. 

I'm looking for advice on whether I should purchase my father-in-law's 6 unit apartment in Burien, WA (10 minutes south of Seattle) as my first deal, or perhaps help find him a seller that would pay more than I could and is a couple years ahead of me in REI. 

I feel as-is, I can get around $120k after cleanup and some minor repairs.

We invested into the property and came well ahead of the local market.

.- This will allow low down payment and the 203(k) allows repairs to be financed into the purchase mortgage.- The 203(k) will allow you to bid on properties that need repairs that won't qualify for a traditional mortgage => less competition => better purchase price.You will need to find a great local contractor you can trust to supply the required bids to qualify for the 203(k).- After closing, you can do some of the work yourself to save money, but the program doesn't allow you to pay yourself.You will want to buy a Class B property, maybe Class C+, in an area that seems to be improving.