I don't own a Colubia, but I've checked out a 29 and a 24 Challenger. The 24 Challenger is still available at the Sea Scouts base on the Columbia River (Portland, Oregon).
I'm hoping someone will check out the 24 and restore it. It has great lines, but needs a lot of work. It's just like the "Pink Cloud" in Royce's Sailing Illustrated books:
I couldn't talk my brother into buying it, even though it's only $850 and comes on a great trailer. The hull and decks look good, and it even has an older roller furling on the headsail. It was once raced, based on the remaining instruments in the bulkhead. The problem is that the interior is pretty much rotted, the internal engine is gone, and it doesn't appear to have sails. It won't be worth much even restored, and doing the interior over again would be a major project.
Anyway, thought I'd mention it. When finished, it would be a fine (but slower) Columbia River cruiser, and the trailer would make it a nice pocket cruiser to pull up to Puget Sound.