I recently visited a battalion that had nothing special laid on for us because of operational committments, yet I found it brilliant. The dead time was spent in the gym or in the naafi meeting soldiers and I came away with what I felt was a 'warts and all' picture of the battalion. Whats more is we were treated like intelligent adults for a change given a choice and a say in what we did and saw, and we were told where to be and when without constant supervision.
edit: saying that probably helped it was in Cyprus as well.
Joking aside, those visits that really give POs a decent experience and a view of what they really get up to are the best. So many Fam visits ive been on in the past have tried to emulate the briefing/main board process, and tell you very little about the particular regiment/corps.
In my opinion the purpose of the briefing is to prepare you for the board, and you shouldn't need any preparation for the briefing, or at least not from a fam visit. The idea of a fam/POs visit is to inform the PO about the regiment/corps and what they do. One of the best things you can do is let POs talk to the lads, as they have a 'no holds barred' approach. Another good idea is showing them some kit and a view of the social life, hosted by the troopies where possible. I understand so many corps are limited in their budgets, but given that OCdts at RMAS are required to make a choice of Regiment/Corps in week three of the course, Fam visits are vital to give an idea of the role of said regiment before OCdts make the plunge.