What I would like to know about Trust Levels.

With the Trust levels, when they are issued to someone for example a Leader giving a trust level member does the person keep that level even though sometime after he/she does not get on for a long period of time?

You should be able to find the answers here:

The “Regular” Trust Level is the only one that can be lost if the user does not maintain regular forum using. (and then regained again, of course.)