If you want to be creative with your routing and get the best bang for your Errorpeso, forget errorplan.com. Best to look up award availability per segment yourself (either using a free service like UA's or NH's online award tool or a paid service like EF or KVS), construct the routing yourself, then call in to AE and spoonfeed them the exact flights, and hope the agent doesn't complain about invalid routing or see any errors. Doing this requires time and knowledge (of all the routing and other obscure rules, etc.), but people are here to help.

As for an actual booking service, I believe there are some travel agencies out there who have people familiar with FFPs and using miles effectively, but you'll probably have to pay them to help you out.

tl;dr: Don't rely on errorplan.com for anything creative.