I actually live in La Rochelle near the Vieux Port so if I can help in anyway do email me ..michael.briant@wanadoo.fr -
Best place to find experienced crew is Crewseekers. Costs you nothing and you will find a Yachtmaster or similar to do it for free along with extra crew - just be sure to check out the skippers real experience not just the bits of paper he has....
You could indeed coast hop up to the channel but my advice would be to go for it in one hit to say Falmouth... If the forecast is good you will do it within a forecast period - if you coast hop it could take a real long time what with shorter daylight hours etc - I did a 200 mile passage a couple of weeks ago and it felt like summer (in the UK!!)
Just to repeat myself - are you sure the boat is ready for a longish passage - do all the systems work - when was the last time she made a passage - In a blow off Ushant is not the time to find the reefing gear is ng..