Really nice cavalier you have got yourself there. Metalic grey suits it well an i maybe im on own but i like it with the original wheel trims.
As for the bodywork im no expert that's a given but you be best to get them bits delt with sooner rather than later as the rot can soon
set in if left especially with all the salt etc on the roads this time of year.
The cost of the arches is all down to how good / bad they are an the standard of the finished job you want too. The arch repair sections can be brought from most motor factors an the dent in the door looks like it can be easly filled and painted. If you can do some of the work yourself then that can help keep the costs down. If not get some quotes from local bodyshops etc an see if you know anybody who could recommend a place they used themselfs an can vouch for the quality of the work. Sorry if you already know all this an it prob isn't much help but all the best with your cav.
![Wink ;)](./images/smilies/icon_e_wink.gif)