Could be. Thanks for posting this.
I notice a few things. The spelling is similar to the blueprint spelling. I don't think his spelling is particularly relevant. He just has different standards for notes to himself.
Derek gets picked up at an airport early Wednesday morning, WIFE (aside: Objectify much? Her first name is shorter than 'WIFE,' and her initials are shorter still) leaves Sunday. Then Derek has 6x6 to cut on the next Sunday.
Rex says he make furniture. Maybe he just means crude tables for torture. Maybe he made that rather nice bench on the porch. But either way, I bet he can cut his own 6x6
Derek flew into town, according to this. He is close enough that Rex is his ride from the airport. Since the likely airports are in Queens and traffic is lighter in July, it could be Rex drove to work and stopped at the airport on the way. By the time Derek is cutting wood at Rex's house, Derek has been in town for a week and a half. Meanwhile, Rex's work schedule is lighter the week WIFE is out of town than the previous week.
MOO
Edited to add another point: Nobody that I know about has questioned these check in dates at smugglers notch. The rather credible questions are about the check in dates in Atlantic City around the time MBB disappeared and was murdered.
I do think it's weird that Rex noted both the name of the resort and the state. It's a place that if you know it,you know it, and "Vermont" is just redundant.
MOO