SPY provided an easy opportunity to long the trend line retest this morning and ride the momentum all the way up - however after that entry, there weren't any other times where I would have felt comfortable entering. It's also important to consider that today was a bank holiday and volume was on the lower end, so signs whether or not this move sustains itself will likely come tomorrow. 
Resistance from Friday (429.82) now should be turned into support if we are to keep up strength. There are some weaker levels that I also have marked that have yet to show significance - 431.44 (support), 433.37 (resistance) and 435 (also resistance). The main resistance ahead is 438.64. This level marks the gap that was left beginning the most recent sell off, and it'd be nice to scale into SPXU and other bear etfs around that level. Unless/until we do, I find it safer to play the range day to day as we are still technically in an uptrend after recovering the trend line. The plan for tomorrow is to trade the range between 429.62 and 433-435. If we lose 429.62, the trend line might provide another retest opportunity.
QQQ also broke above it's gap today and as long as 364.54 holds tomorrow, we could see another attempt at the downward trend line above.