How prudent of me would it be to make terrain out of brushes and patch meshes? If I want to use the EasyGen editor, what resources left on the internet are there that I can use to teach myself? Would anyone who still comes to this website know how to use EasyGen or advise me on what the best thing to do next is? My map currently contains 3646 brushes and 156 entities.
These are an older way of making terrains.
A newer, better option would be to check out the map source for Pyramid of the Magician by Sock.
Basically, a combination of small detail brushes placed over the top of structure brushes. This is the key: many hand tweaked detail brushes on a base of structure brushes.
Patch-based terrain introduce clipping issues, and there's also the sometimes-blindly-suggested model-based terrain which will lead to extremely bloated clipping hulls that will force you to make some hacked up simplified variation of the map for compiling .aas files at all. Marks will also have trouble being added (especially if it's complex terrain where there may be too many polygon splits).
Many of the techniques in Pyramid of the Magician were at a time when q3map2/bspc wasn't well suited for terrain and large maps. There's been some improvements on that since.
Edited 2.02 minutes after the original posting.
Edited 21.96 hours after the original posting.