Firstly I'm not professional pilot so feel free to disregard the following.
I'm currently in the TA and I'm trying to find all the bits of paper I was given when I joined so I can give you more informed answers.
In general all of the above is true except that the current legislation makes it a legal obligation for your employer to keep your job open if you are called up (and I think the govt provide compensation to cover your absence). But siknce the Strategic Defence Review the TA has become a more integral part of the regular army and is no longer only liable for call up for major conflict. It depends on your unit's role but we were close to getting called up for the foot and mouth crisis.
However there appears to be no legislation compelling your employer to give you extra leave for your annual commitment which is only supposed to be 2 weeks, 3 or 4 weekends and x number of parade nights per year.
I'm currently going through the process of getting a commision and I HAVE to do something every other weekend and I could really use 8 weeks for the courses and camps (2 weeks Sqaudron annual camp, 1 week pre commisioning course with the University Officer Training Corps, 3 week commissioning course at RMAS, and 2 weeks troop commanders course if succesful) needless to say I'm having a nightmare with my boss who is being pretty unhelpful for most of the reasons given by Wycombe and that was just when I asked for two weeks off for annual camp!
Pilot Pete also made a VERY valid point.
My normal weekend consists of:-
finish work at 1700
Race home collect Kit and get to unit.
Fri night usually spent preparing to move out of TA centre and get on road by around 0001hrs, If you're lucky you're NOT driving so you can get some kip on the road.
Usually 2-3 hours drive followed by parking and hiding the vehicles. Then depending on sentry duty sleep until 0530 when reveille and breakfast.
We then work on various tasks until they are done, this can and does go on until the wee hours (last time it was 0330 on sunday)
Reveille is 0530 again and then you would usually work and travel back to arrive at your TA Centre for mid afternoon. Then its strip out and store the kit and vehicles and off home for tea and medals.
I usually find I'm fit for work by mid wednesday and I just work in an office!!
But all of that aside you can do as little or as much as you like, it all depends on what you want out of being in the TA.