I don't think your real question is a strategy to enter the market. I think you have not yet decided that you even want to enter the market.
From that perspective, you really want to figure out for yourself what your realistic goal is to be financially independent and then create a strategy for investing. If you decide that you have enough to retire right now.....and that's what you are going to do......and you can tolerate zero downturn in the market, then off to Ally (or some other place) to find the best CD ladder you can find.
The market will go up and down with a trend over time of going up. If you don't believe that, then you have no business looking to invest in the market.
If you have decided that you do indeed want to invest, what would be your asset allocation? Figure that out. Perhaps for you, you'd choose different classes of investments than the normal 3 fund stuff. Just a wild ass guess....maybe the below would work:
Total US Stock: 10%
Total US Bond: 20%
CD ladder: 50%
iBonds: Whatever you can buy up to your/spouse limit. Say 5%
Pay off your mortgage. Say 5%
High yield savings: 10%
This would be a wicked conservative allocation that you won't lose much of anything even if the stock market pulled another 2008. Will your gains over time be worse than someone at 50/50 stock/bond? Yah. How about 60/40? Oh yah. That's the trade off. There isn't a low risk 12% investment vehicle out there. You can get your 1.25% Megamoney account at Redneck Bank (that's real, by the way) or you can put your money into Total US Stock and let it ride to perhaps gain 10% this year or perhaps lose 10% this year.
Personally, I'm retiring in 2-5 years, have a 50/50 asset allocation and have been dumping extra money into SCHB and today (right now, since the market just opened), VTI.