Trap seems like a fine idea...

If it were not a multiband loop, I think you could use a relay with the
coil in parallel with the contacts, so you could run DC on the feedline
(if it were a dual bander of some sort) but the high voltages present
on the open wire feeder would make it awfully hard to choke off the RF
for whatever DC injection scheme you were using. I think you'd
basically need a tuner with DC continuity, and the CLC tee that is so
common in tuners isn't one.

I guess you need a big enough C on the higher bands to look like a
short circuit in that trap if you want to have the loop appear to be a
closed loop, but maybe that's not very important.

73,
Dan