If your close to the port then parking up on the port maybe your easiest option, we tend to make sure our last site is about 3 hrs from the port so we can take a leisurely drive with stops at aires so not to arrive to early.
Portsmouth to Le Havre Brittany Economie is normaly a cheaper crossing, and ATMB should be starting there annual free evasion toll tag offer soon, you only pay around 4 euros postage to get the tag and just a one 1.60 euro charge for the month you use it on top of the normal toll charge.
We have spent the last 2 New Years here http://www.campingcaradon.co.uk/ reinforced grass pitches, bar and good restaurant on site, bus stops in main entrance for Looe, Polperro and other places, and a super buffet and Disco New Year Eve, + Bingo and quiz nights on other evenings £17.50 a night inc 16amp hook up
Sorry to burst your bubble there Ian but our insurance on our £72000 pound motorhome is £282.00 fully comp for the year new for old for 3 years as long as we do not exceed 20,000 miles if we opted for the European breakdown cover it adds about £50.00 to the cost, which is less then the £350.00 it cost to insure our caravan 3 years ago. This is through Comfort Insurance, the Caravan Club quoted silly.
The plastic screw pegs are pretty useless on anything but grass, however these are a good alternative with a washer under the head.https://www.toolstation.com/shop/Screws+%26+Fixings/d90/Coach+%26+Roof+Bolts/sd1670/Coach+Screw/p14423