I did purchase his program upon joining BCG, and even kept it for a little while afterwards. Honestly though, I felt it was (a) not nearly as impactful as his programs geared towards applicants - such as LOMS, and (b) probably more useful for a 22yo than someone with a bit more work/life experience.
Would I recommend it? Probably not, honestly. Travel, relax... perhaps read a couple of these resources you mention or do some excel, but above all enjoy these last few days of bliss - pretty soon, you'll be wishing for more downtime :)
PS: congrats on the offer!