I installed a 1/4 aircraft plywood plate in front of the servo tray, against the former at the front of the wing saddle. I installed 1/4-20 blind nuts and used nylon screws to attach the main gear.
I used a tail wheel assembly similar to http://www3.towerhobbies.com/cgi-bin...?&I=LXCLK9&P=0 and ran a pushrod from the rudder servo to turn it.

Some people drill through the stabilizer and run a steering wire through to the rudder. Others mount a servo under the rear of the fuselage and attach it to the tail wheel. My 60 size Big Stik needed a fair amount of lead on the tail so installing a servo back there may be a good idea.