Wood is a fine material for off-season construction, just be wary of a few things:
- Axles, even dead axles, will need more support and care than that of an aluminum frame
- Pilot holes are you friend
- If you're unsure of the impact capability of a specific area, wrap it in fiberglass, cure with resin, and sand.
- Measure several times, drill/cut once.
- Wood isn't as "strong" in a tensile manner than aluminum, so care should be taken designing around shear forces and load bearing surfaces
- Wood compresses, (most) aluminum alloys do not. Plan accordingly.