I suggest fiberglass patch and paint also. A body shop would be the best permanent fix.
If your going to caulk the hole then put some expanding foam in the gap and sand it down flush . Then use Dicor self leveling roof caulk. If you caulk then you must maintain the caulk evey year or two at the most. While I am on the subject of caulking... i do alot of rot repairs annuallly. People just dont maintain their coaches. You must recaulk!! On all exterior walls, caulk moldings, windows, doors, marker lights, every where there is a fixture on the wall. Use a silicone caulk. For the roof, use a self leveling roof caulk like Dicor or Royal roof. On the roof, caulk everything that has caulk on it now . A little maintenance prevents thousands of dollars in rot repair and insurance companies wont cover lack of maintenance, even if it is still on warranty manufacturers wont cover it either. Most manufacturers warrantee caulking for 90 days after that your on your own. After a year caulking cracks do to flexing from road travel. Water gets in the cracks and once wood and insuation either foam or glass gets wet it stays wet until the wall skin is removed and allowed to dry out.
