Look where the wiring currently runs from the battery & mini circuit breakers in the A-frame. If you are lucky, there will be a suitable hole that goes up into the forward side of the pass-through compartment. You'd need to peel away the luan to access the wiring, then re-install it. Maybe you'd find that there is a length of wiring loom to protect the wires. Once into the pass-through compartment, it'd be easy to go the under-bed storage.
Our TT has a hole into the pass-through but workers at the factory just whack a hole through the frame and make no attempt to remove burrs. I managed to get two #8 wires through the existing hole but it was a very tight fit.