Sounds like you have a good idea (generally) of what you would like to do. And, it looks like there is a lot of good advice in the replies.
I would start at the simple, granular level. Like, how much money do you need to cover living expenses, how much do you want to make over and above expenses, what do you want your day to day activities to look like (Do you want to deal with tenants directly, do you want to research and find deals, do you want to manage your str's directly or find ways of making enough money to acquire them and just manage the managers, etc).
It sounds like you have some clear "general" idea of what you want (i.e. to replace your W2 income). And it sounds like you have honed in on a part of the business you are interested in (i.e. str). But, you also mentioned the possibility of multi-family. So, maybe you have a little more contemplation to entertain other parts of the business you may want to focus on.
But, once you have your monthly income goal, than you can zoom-out and back into it. So, if you decided to start with str's, you would choose some areas you may want to work in and do research, finding out the #'s (property prices, potential income, estimate how long it may take to acquire a property and get it to stabile income, etc), and decide how many of those you would need to get to the monthly income you want. That would give you the framework for the plan (i.e. If I acquire 1 str in this location, for around $300k, I should be able to get it to a stable net income of $2,500/mth in about 6 months, utilizing a reasonable 10% unleveraged net return, etc). Then, if you wanted $10k/mth, you would just need to write the plan of how to acquire 4 str's that would perform at least that well.
And, if you are netting $400k after taxes form your personal house sale, you would work out the #'s of how much of that it would take to acquire your new primary res (personal home), and how much left over to invest in the str's, including reserves, etc. Then you just choose how to go about acquiring those properties, and adjust as necessary.
I am guessing you probably already thought of a lot of this, but hopefully, that was somewhat helpful. But, I am wondering if you need to hone in a little more on which aspects of RE investing you want to focus on. There's a lot of it, and I have seen people get overwhelmed and try and do too much of what they realized they didn't want to do in the first place. (mind-twister)
Other things that make you go Hmmm...
1) Understand the tax ramifications of selling your personal house. $250k/$500k exclusion, etc. If you are single, sounds like you will have some gain, if not single, than it may all be non-taxable. This may not work with your plans, but you do have the option of moving out and renting it for a year and then selling it and 1031 into investment property/ies.
2) Not sure if you are able to work remotely when you move, if not, be clear on how you will finance your deals (cash, loans, etc). If you are able to get good loans with your W2, maybe you want to acquire some deals now, when you can better qualify, before you release the W2 income.
---- Curious
Where in TX are you contemplating investing?
I have properties in 3 different TX markets and am just curious as to where you are thinking and why?
Ok, that's enough rambling... :)