It is if it's doable but probe with the pointed end of a scribe around key areas to see just how bad the rust is. There is a point where it's not only beyond economical, it can be beyond feasible to repair. If that's the case you may want to modify the limit of how much more you want to put into it.
If the body is a good candidate for restoration then you have to decide how you want to go about that and what level of restoration you want to achieve. If your desire is to bring it back to a like new condition then there's little use in spending money just to get it drivable in it's present condition. You seemed to indicate you bought it to restore but if you just want a drivable beater that's a different story.
Paul - 1972 Spider - (2)1991 164S's - 1983 308 - 2001 Discovery - 1997 F350