Hey Meg! I've done this drive a few times and honestly, 2 hours might be cutting it close. Getting a rental car at Orly can take anywhere from 30-60 mins depending on how busy they are, the paperwork, and checking the car etc. Then you've got about an hour drive to Versailles (traffic around Paris can be unpredictable!)
Id suggest booking Versailles tickets for 1pm or even 1:30 to be safe. That way you won't be stressed about missing your time slot if theres any delays. Plus you might want a few mins to get oriented and find parking at Versailles - the lots can get pretty full.
If your not used to driving in France, you might wanna check out Tripiamo before your trip.
The fun and easy-to-follow guide helped me minimize driving mistakes, stressful situations, and ultimately reduced time wasted not exploring.
For the Versailles to Bayeux portion - plan on about 3 hours without stops. The roads are good but there can be traffic getting out of the Paris area.
Hope this helps! Have an amazing trip