For example I know many who are now just lending because they are getting 10-12% short term which is far better than any cap rate on real estate. you do not have the equity upside as you do real estate but its a way to play the short game to see what happens over the next 12-24 months and decide when you want to buy.

Personally If you like your current residence and hope to stay there long term I would forgo major improvements on my primary and use all investment savings to make you more money and cash flow. 

She can use that money to get a hotel room or short term rental....or stay with family or friends.

Quote from @Andrew Lawlor: I've been actively investing in short-term rental properties for the past three years, managing one live property and another that will go live in two months.

This STR would also be a place for us to block dates off for ourselves between work contracts (if we want to), which adds a slightly more personal investment in this one. 

Used PSI last year, they did a bad job, the snow wasn't even bad last year and with several attempts asking them to do better within the terms of the contract, they still sucked. 

For more expensive properties you'll be wanting to pay a lower interest rate and doing short/mid term rentals.

How strong is the demand for mid-term in Denver?

I have 2 properties now one I live in but Short Term Rent it when not home which is a lot.

Rental properties come in several flavors... short term, long term, etc.