If you are sat on the ground you are safe. When planning a take off and initial departure you should satisfy yourself that it is safe to do so. If the weather by itself or in relation to terrain etc. is giving you serious cause for concern then delay the take off until the situation improves. It is all to easy to fall into the mindset trap of assuming that nothing must delay the flight.
If subsequently the choice is terrain or cloud, pick cloud every time. An encounter with the first will probably kill everybody, the second might provide for an unpleasant ride for a while.
SID,s are just that Standard Instrument departures. They are constructed with regard to many things including terrain clearance, airport arrival and departure flow, noise and other political considerations etc. If the situation is not Standard (with regard to weather) or a departure where visual conditions may better substitute, then liase with ATC and negotiate a safer departure.
There are often occaisions when a compromise has to be made and Captains are normally selected for their demonstrated ability to exercise such judgement. Of course that does not infer that such decisions are universally correct, nor does it infer that they will be made without necessary input and advice from others. However it is important that a timely decision is made.
As regards legalities, rule distances and other perceived violations good planning should normally negate any worries on all of these matters, however where for whatever reason there is a need to compromise then there has to be a simple set of basic rules.
1. Don't risk flying into rocks.
2. Don't risk flying into weather that might damage anybody or anything.
3. If faced with a stark choice between 1 and 2 pick 1.