A clean boost like the Keeley Katana, leave it on all the time at the beginning of your chain is one option. Or you can get one that is a boost and buffer that will buffer your signal even when the boost is not on, for this there are two pedals I prefer, one is much more pricey than the other, but worth the investment IMO.
http://proguitarshop.com/mi-audio-boost-n-buff-pedal.html
MI Audio Boost n' Buff, I used this pedal for about 3 years until I recently purchased this one
http://proguitarshop.com/tone-monk-ankh-preamp-vp.html
It warms up my clean tone so much, I always leave it on, but it also has the best buffer I have ever heard in it, even when the pedal is off my whole tone sounds better for having this pedal in the chain.
Also, another cheap option would be just to buy any pedal you've wanted with a buffered by pass as opposed to a true bypass. The buffer in the signal will help restore some of what you're losing from long cable runs. A TS808 for example has a built in buffer that doesn't sound too bad.