The rental market is picking up with the covid-related restrictions fading, but I'm concerned they may return with the recent uptick. 

I may have to pick your brain when it's my turn. 

I think that the main recreation season is only about 6 months so I would like to figure 50% occupancy to be safe which means $30000 per month on average for STR .

At a higher price you could find something that has a garage apartment or somesuch ADU . . . then live in that and rent out the mainhouse (LTR or STR, pick your poison!). 

separately, could i pick your brain about your adu garage conversion?

Buying a tenant occupied house is rarely successful, most of them stop paying as soon as you close they might have a prior agreement with the seller or just jumped on the occasion, when investing out of state always pick a vacant house and make sure the tenant is properly vetted by your manager. 

In that 3 year period maybe you also invest out of state and pick up a few properties in different areas with your cashflow savings, or rent savings. 

Pick a solid B-Class suburban area.

Your labor is not accounted for unless you are paying yourself as a contractor and picking up that income at the individual level.  

But as someone else said in many groups, make sure you do due diligence on all the cities you are looking to invest in and pick the best that suits your profile, goal, and investment style.