I actually looked into that route but mine wasn't high enough either. From internet research, I don't see that anyone has been able to desynth the lumber. It's possible someone hasn't recorded it but multiple sites listed the only acquisition point as the chest in the dungeon.

And I found I needed everything for CRP. There were one or two housing items I was able to skip on BSM and ALC but I had to do both tabs on CRP and everything in the non-master books. I'm lucky I garden so I had glazenuts on hand and manor varnish is not something rare on our MB. Which were you able to skip?

I finished my CRP tonight because mercifully the last 3 lumber I needed appeared on the MB.