I would suggest getting another full-time job for the time being and investing/doing STR on the side until you can fully and comfortably replace the income that you would be receiving from your job.Is your LTR in need of repair?

Index funds beat those returns by a long shot and don't have furnaces to replace or tenants to deal with.As I see it, the only way to actually cash flow in the current market is to do a higher effort strategy (STR, MTR, rent by the room, etc.) or have low to no leverage. 

., plumbing, window replacements, and sheetrock repairs), but it still needs work to get the vacant units ready to rent.It’s located in a neighborhood with a higher crime rate but also near major highways and areas with rental demand (e.g., downtown Fort Worth and Texas Christian University).My Goal:I’m focused on cash flow, and this property seems like it could work if I can stabilize it.

The roof, AC, plumbing, electrical and flooring will eventually need replacements.

Don't split the work between multiple contractors if possible, finding one to do all or most of the work will keep prices down.Challenges were finding replacement pieces for certain items as manufactured homes were very different than stick built as well as going through state guidelines for affixing the house to the land

If finding a new replacement is more difficult then get your new property under contract first even before your old property closes.  

In a 1031 exchange, the replacement property must exceed the total sales price of the property sold ($700K in your example), not just your equity portion.

The job consisted of replacing most of the front entrance, which consisted of 3 wood steps and a small platform deck the size of a standard refridgerator with railing. 

Sometimes it makes sense to pay the gains if there are not adequate replacements.

I also renovated hallway and replaced all staircases with a new oak staircase.