Descending through cloud without a procedure
I have a question about flying on top of cloud.
Pilot takes off in good viz with a layer of cloud 2000ft above the local terrain. Pilot gets a RIS and climbs on top for some general handling then decides to descend until in sight of the surface again. If in Class G airspace, and not using any procedure, but perhaps tracking a VOR and fairly certain of location, how low can you go, assuming the cloud base had lowered since climbing on top? Is this a judgment call or should it always be 1000ft above nearest obstacle? One can well imagine the temptation to try a little bit lower. Didn't Hill crash at Elstree doing that?
Could it still be acceptable to descend below MSA if you knew exactly where you are? If you were to unable to break cloud, presumably you'd have to divert to an airport where there is an instrument approach, but would ATC give you ILS frequencies or would you have to be carrying full approach charts everytime you go on top?
Yes I do have an IR, but no I have not really used it, and frankly find the idea of using it is daunting since the training for the IR was a entirely on pre-planned school routes.
Also, if you want to navigate out of sight of the surface, but there are no radio aids suitable to track, is it acceptable to dead reckon and back up with position fixes, or should you always be tracking a radio aid?