Moving to a rental makes no sense. You'll be spending 5k more annually for housing than you do now, but you might break even with the extra rental income from your residence. It sounds like you'd be able to depreciate about 7k annually from your income--- that is the tax advantage you're talking about. Its definitely not worth moving to a new place, becoming a landlord, dealing with repairs and tenant issues, and your house will probably be more worn down when you eventually want to move back in or sell.
I question moving myself all the time if goal is to save. I just was trying to look for ways to get tax breaks like the depreciation you mention. The tenant give great pause.
Don't overlook the significant tax breaks you get as a homeowner. Mortgage interest deduction, property tax deductions -- and that up-to-$250K in profit when you sell. Given the current tax codes/standard deduction, those first two might not matter, but the third does. If you convert it to a rental, you will need to subtract any of those depreciation deductions from the basis of the house when you sell it, meaning you ultimately have to pay those taxes anyway when you sell, unless you do a Starker exchange into another rental property. IMO, whatever small tax benefits you might get from this scenario are not worth all of the hoops you're trying to jump through -- it just makes no sense to commit to spending an extra $20K/yr
on top of your mortgage, just in the hope that you can rent your house for more than that mortgage-plus-$20K/yr (and remember, rental income is still income that you need to report and pay taxes on, and you can't guarantee that any depreciation deduction will offset all of that).
FYI, the single-most important factor in how soon you can retire is the percent of your income you can put toward retirement. See
https://www.mrmoneymustache.com/2012/01/13/the-shockingly-simple-math-behind-early-retirement/. If you just keep your expenses where they are and bank the rest of that large income, you will be putting yourself on a great path, without much actual effort or thought.
Also, on the 401(k): the primary benefit to a 401(k) is that it allows you to shelter a much larger amount of your income from taxes than any other vehicle. Sure, if you don't get a match, and you have only $5-6K/yr to invest, might as well do an IRA instead of a 401(k), because that gives you the best ability to minimize the fees associated with those investments. But your ability to contribute to an IRA maxes out at $7K, whereas a 401(k) maxes out at $23,500. So if you're trying to maximize the amount you can put away before taxes, the 401(k) gives you the best way of doing so, unless you're stuck with a truly terrible one.
My primary thought: don't let the perfect be the enemy of the good. Focus on stashing as much as you possibly can into a basic index fund or index ETF. Put as much of that into a tax-deferred vehicle as you can. Once you get to that point, if you still have extra time/energy to focus on your finances, that time will probably be better spent trying to earn more, rather than getting into the details of trying to optimize all of the other potential decisions you can make. Investing is only as complicated as you make it.