First off, let me start by stating (again) that Camp Roberts is an ACTIVE Army National Guard training center. It is manned by 24-hour MP guards who also regularly patrol the main cantonment area.

My trip to this site was 100% legal. Getting on the site is very easy. When you enter the main gate from 101, just before the guard house, turn to the right into the parking lot where the PMO is located. You must go inside and register to get a visitor pass and vehicle permit. To do this, you will need to present a valid driver's license ID, proof of insurance for your car, and your current DMV registration. You will have to sign a visitor book stating your purpose of visit. Just put "Museum". The MP's will then provide you with a dash card for your vehicle. Make sure you ask the MP's at the PMO for a map of the site. They will gladly provide it as well as note a few key points of interest on the map.

When you get to the guard house, present the dash card to the MP guard(s) and they will let you through. The MP's carry sidearms, so don't even think about doing anything stupid

Once on the base, you'll want to first visit the museum. The museum is open Thursday and Saturdays from 9AM to 4PM (see URL in the Web Links section). Try to go on Saturdays as the additional museum "annex" will be open and you'll DEFINITELY want to visit that. TONS of military history in both the main museum as well as the annex. The annex has all the really cool larger stuff (tanks, vehicles, you name it!).

You are free to drive around the site...even to the HQ buildings, but the supply area on the main garrison as well as the one at the East Garrison across the highway are OFF LIMITS.

As for the abandoned buildings, you can drive on the main roads right adjacent to them, but you are not allowed to drive down the individual side roads by the barracks or enter any abandoned buildings without the permission of the garrison commander. Please take note of this! If the MP's catch you entering the abandonments, they will conduct a field investigation and either tell you to vacate the premises (i.e. leave the camp) or even arrest you! Do not cross the line! You are a guest on an active military facility and all federal laws apply.