If you do that over 10 days then what distance minimum do you have to ride each day?
Then work out if you can ride that distance everyday AND more importantly if you don't ride that distance on a particular day* can you make it up the next day?
I always plan conservatively and then usually end up getting somewhere earlier than expected or use the extra time for detours/changes of route as I go along. I'd rather do this than not enjoy it because I'm chewing my stem through stupidly long days everyday though.
*due to weather, hills, mechanicals etc.