For an unrenovated 1+Den/1BA LTR in our section of Northeast though, $1,300-1,400/month is certainly in the ballpark of what I could comfortably get with some very minor improvements to the space between tenants.So all that being said, I think your target of $1,500-1,600/month for your 2BR units would be more than doable. 

I see enough of these, I think it must not really be an option or some young entrepreneur would be taking on these projects.Are they big enough for me to have the kids and grandkids stay over?

You Pay, You Stay. 

I hope you and your family are doing well and staying safe.

Personally, all of my units are full and have stayed full, no one is even late with rent much less behind, and no one is moving.

Is it worth buying vs renting given I'll be staying there for 3 years.

It won't stay that way forever, so enjoy it while it lasts

(I was a stay at home mom when I did my last big project, and really had all the time in the world.)

Personally, I like to update it weekly—it helps me stay on top of things and, honestly, I find it fun!

Single night stays in a crowed city are a guarantee for a party.