Essentially, I have been using QuickBooks for expenses and overarching record keeping, and excel to keep track of the breakdown of the categorical/long term expenses (or allocations from rental income towards long-term expenses).

It sounds like you're on the right track! 

Anyone have a phone app they would recommend for tracking travel? 

They tracked debris in everywhere, carpet cleaning had to be done twiceDidn't take showers before going to bed, so all the sheets were ruinedRuined the towels when they did take showers as they werefull of construction crapLeft garbage piled up inside instead of putting it in the exterior trashbinsOverall, we still made some money, but have turned down all construction crews since.IF you were going to pursue your strategy, suggest you rent out by bed (not room) and supply some hygiene basics.

However, my wife is hesitant to involve our current residence, because she does not want to put the property at risk if things do not work out. 

We sub most of our work out ourselves and we understand the labor costs because we use the same subs over and over again.

How did it work out for you?

Is there a way to get that money back if the deal doesn't work out?

We can easily cover the mortgage with our W2 income and we anticipate we will cover the mortgage and then some with the STR income (it has a track record of this with current owners and also comparing data from surrounding comps).

What I wonder is how the LLC gets enough of a track record to start qualifying for loans?