For Caslav:
The main road around town also passes the airbase closely. At some point, there is a small road leading up to the airbase from the west side, ending at a small gate. From there you have a good view of the runway and platforms (all platforms, shelters and hangars are at the opposite side of the runway). We parked our car away from there, near a cemetary on the other side of the main road.
Also you can go a little south and get near the approach lights.
We visited Caslav on the Sunday of Brno show (this year), as part of the fliypast was flying from Caslav. The gate we were at was used by many people (including military police) to enter and leave, but we weren´t approached once. We didn´t take pictures though, maybe that makes a difference.