There may be other unforeseen breakage primarily in the handbook portion of the wiki.
The Table Of Contents section of each "PC-BSD® Users Handbook" page may be the best workaround.
It would be helpful to have any idea what some of the errors these various problems give as output, even if it is a panic shortly after an attempted boot. Knowing what the problem looks like in those situations where the hardware may not be fully known, would be a great help in making suggestions for possible fixes- and also might help with generalizing with errors that have similar solutions.
A truly odd situation with CQ62-410us compaq/hp laptop which fails due to some kind of apparent BIOS error- pressing escape in order to cause a boot device selection of DVD seems to solve the problem and allow boot to continue. Reference forum post near the end, last 2-3 comments, http://forums.pcbsd.org/archive/index.php/t-13590.html