The 18 tooth gap between the 42 and 26 is pretty large and you will be prone to dropping your chain...

I do 38/26 without trouble (most of the time)...

Get yourself a Chain Minder or Dog Fang and it may help...

You will not really need the 42 for Washington. If you spin yourself in the 26 passed the Toll Booth to the first incline you will most certainly not be seeing the 42 again...

You won't be able to shorten the chain if you leave the 52 on the bike. The chain wrap needed is measured from big to big...