If there is coolant in the oil do not drive it. you will risk spinnging a bearing and cause internal engine damage. If there is oil in the coolant it will be ok to drive just make sure the coolant is toped off.
As far as rust in concerned, rusty sway bar mounts and rear sub frame mounts are the worse. Body rot as long as you dont plan on winter driving it isnt a big deal. Most body shops can patch holes and make it look like it never happend.
If its leaking coolant by the head and its near the timing belt cover it could be a water pump. Its a farly common wear item will cause a leak that looks like its comming from the head.
As far as rust in concerned, rusty sway bar mounts and rear sub frame mounts are the worse. Body rot as long as you dont plan on winter driving it isnt a big deal. Most body shops can patch holes and make it look like it never happend.
If its leaking coolant by the head and its near the timing belt cover it could be a water pump. Its a farly common wear item will cause a leak that looks like its comming from the head.