Selling primary to invest

[Nathan Ruffrage]

Greetings. 
Looking for general investment property strategy advice. I left a teaching career a year ago to be a full time investor and now looking at ways to grow the portfolio. I’m  middle aged with two young boys and a wife who is very supportive and currently working full time but wants to take a step back to part time. 

Current assets are- 

-Primary residence holding 300k equity. 
-One LTR has a HELOC of 135k available and rent is 1750 a month.
-One STR with 80k mortgage and generated 25k gross last year.
-One flip (possible hold) in progress using LTR Heloc for the financing. Will asses when completed in 8 weeks on which direction to go. Speculative growth in that area may lead to holding for a little while. 

We decided to cash out on our primary and we are under contract to sell end of month  ( still could back out) which will net 307k. We have given our tenant notice we will be moving back to the LTR which was once our primary 5 years ago.    

Our current plan is to take the the proceeds and funnel those into more investments . Looking at higher end STR.

Thoughts opinions are welcome here. Thanks!