Sometimes you have to think out of the box, re: toll routes. OK, first of all, time for you may not be an issue, from viewing a french tv prog last year, there were two reporters doing a toll route, and non toll route challenge. From what I recall, and I may not have all my facts correct, toll reporter landed at destination first. Non toll reporter took two hours more to reach destination, much due to stop start within towns, villages, roundabout, etc. Then there was the extra fuel used to factor in, which was more fuel used than the toll reporter. The conclusion between both reporters was very interesting, and in my own opinion, use of tolls may look expensive, but when you weight it all up and look at the bigger picture, ease of travel, hit cruise control then sit back and take in the views, brilliant road surface conditions compared to UK shit roads, including motorway. Plus the fact, and I have used this options a few times, pull into a motorway aire for the night, all have facilities for the traveller. The £200 saving will be less than this when you take in the extra time and fuel cost to reach your non toll route destination, I should also add, less stress too.
Our recent three month trip we used the toll tag system, which made passing through the various peage a great experience. The above is my opinion only.