We have seen quite a resilient market. Considering the low volume in the market and on stocks, you would have expected some sort of pullback already, and yet both keep pushing higher. It seems the sellers are holding out for more volume, because when they do come in from time to time, there is generally a very hard reaction.
So what if you've sat this one out? About the only thing you can do at this time is to take multi day swing trades and patiently wait for the next pullback opportunity. Is it possible this market just keeps going...sure. But you will get rotation amongst the leaders pulling back to their 20 or 50 dma's. Otherwise the risk is too high to enter the majority of stocks at this point to hold for an investment.
Unless we're going climactic, I can almost promise that you will get a chance to buy most of the leaders that have been moving higher at or near current prices after the next pullback. Except you won't have to sit through the eventual pullback. Now the only question is, will the next pullback be buyable? Only time will tell. I do know one thing, it will be at the worst moment when the best opportunities will present themselves.