Ditto what Kirk said on the pushrods. Also, I usually like to figure out the engine mounting position and then look at the tank position before finishing up the front of the fuselage. As the range of engines is so wide the stock tank position may or may not be where you really need it and the time to fix those things is while building rather than after.

Another small hint is to look at where you expect to have items like receiver and battery. Then while your building, think about how you want to secure these items. Sometimes I drill small holes in formers or glue on extra bits of balsa for rubber band anchor points, etc. Once again much easier to do while building. Also, try and decide a little early where you want things like switches, etc. You can adjust their position for easy access or to try and hide them if its a scale job.

Duke