You would have to move the mains forward to probably within 1" of the leading edge of the wing. I personally don't
think with the configuration of the tail lower fin extending to the rudder that a tailwheel is really practical. It would
have to be driven by a control arm extending from the side of the fuselage or a rod inside the fuselage running down thru the lower fin on the fuselage. Then you have the extended control linkage from servo to the rear.

I don't know what kind of field you have, but these planes are flown from grass all the time.

Could it be done, yes. But, I think the character of the plane would be diminished.