Housekeeping is the single biggest headache for us, and we are right there.

If not full owner financing My biggest concern will be finding ways to make up what the loan doesn’t cover.

I would not sell off your portfolios, the biggest reason is that you will get hit with taxes on them this year that could create some bigger tax liability that you may need to save. 

This is really the biggest hurdle that most people never cross so pat yourself on the back for getting into the game!

Payment concerns:-->Get 2 more bids, ask about longer financing, put it on a credit card, put more down on it, go with a less expensive unit.Call the biggest and best installation company in the area and see what their payment options are.Go with a lower cost brand name.Find out if any of of the property's utility companies offer cash-back or cash-assistance for certain replacements.Just my 2 cents.https://www.youtube.com/watch?

I think the hardest/biggest hurdle to overcome when doing something like this is the permitting with the city/county youre dealing with.

The biggest thing is you'll want to ensure you have enough time for a commercial appraisal - these are much more extensive than 1-4 unit properties and cost 3-4x as much usually.

There are thousands of properties listed for sale in the MLS's across the country.Your biggest question shouldn't be WHERE to invest, but HOW you will invest!

The biggest problem right now is debt so I'd work on getting your construction financing in place and making sure your underwriting still works before raising any equity to fund your deal.  

Biggest lesson is that I need to buy another home next year: no staying put for too long.