The dent is probably the easy fix . It's Always best to straighten a frame
cold, but in this area a little heat won't hurt. The stress cracks are a more serious concern. Before You try to fix them take it to a reputable frame shop
and have it checked for Square, Level,and twist on all planes. Then have a Pro. do the welds. Rearwards of suspension is not an area to learn how to weld on. Looks like it's been on a Baja Run. Good Luck , Jimmy
This one looked like that,but not cracked. http:
www.lateral-g.net/members/jjohnson/