OP doesn't have a 401k, so a Mega Backdoor Roth isn't an option.
Dang, keystone, you are killin' it. Paid off $134k of debt, plus $26k of 401k, in 7 years on a low income? That's awesome.
If you really want to understand when you can downshift, you'll need to build yourself a spreadsheet that starts with your current assets, plans out your investments and expected returns, and shows how, once you eventually start to withdraw those funds, your assets might perform. I have one that I've built, and not only is it great for planning the future, it's fantastic for seeing how tweaks to the plan can affect it.
As far as where you should put all your extra cash flow, the Investment Order thread (linked above by freedomin5) is a great place to start, but I'd suggest some tweaks. The fact that you have no debt, have no access to a 401k, have far more money available to invest than the $6000 you're allowed to contribute to an IRA, plan to retire early, and are currently earning WAY more than you spend, I'd suggest the following:
1) Max out a traditional IRA (you're single, and the 22% tax bracket starts at ~$40k)
2) Invest the rest in an index fund
Since the bulk of your investing will go into a taxable account, the concept of the Roth Ladder is irrelevant to you, so things are a lot simpler.