All initial contracts are for 8 years. 6 as a drilling guard member and either 2 more drilling or as a member of the inactive ready reserve (irr). IRR is basically a list of service members who can be called to active duty if needed. In the beginning of the wars in Afghanistan and Iraq a large number of irr soldiers were called up. However, there are virtually none now. As a guard you drill one weekend a month. Usually it is Saturday and Sunday. Sometimes you have to report on a Friday night if you are going to the field. Your drill pay is based on 4 hour blocks. Each 4 hour block counts as one day of active duty pay. You also have to do a 2 week annual training. This training can occur at anytime in the year but most guard units have their training in the summer. Usually you go away with your unit and train in the field. Sometimes, you go to special training instead of going with your unit. Your annual training pay is different from drill pay. You only get one day of active duty pay for one drill day but you get partial basic allowance for housing and your meals are provided.
As far as the training, it depends on your unit. Some units have really good training and some do not. Usually you have section time where you do section work. If you belong to the supply section, you inventory and do paper work. If you are admin, you work on admin tasks. If you belong to the motor pool you do maintenance on vehicles. You also have mos (job) training which can be hands on or classes. There are mandatory briefings throughout the year. For instance, the JAG will come to your unit for briefing on wills and power of attorney. You also have pt during the weekend and at AT. You have PT tests 2 times a year. During the holidays, most units have family functions. If you belong to a good unit, the time flies. If you belong to a bad unit, you look at the clock.
Remember that annual training can occur when you are still in school and you have to make arrangements with your faculty to make up work. This is the same if you have a civilian employer.
Also, some states pay full tuition for guard members enrolled in state universities. This is a good benefit but make sure that your state does this before you enlist.