Hi Rob, no spoilers from me - so relax.
I did a solo trip to DLRP in June 2007 while on business in Paris. Their Tower of Terror (at the second gate Walt Disney Studios - WDS) was about 6 months away from completion and I had to leave the day before Crush's Coaster was to open at DHS. So you have some things to see that I missed.
One of my favorite things was their Tarzan show which sadly has been discontinued. I checked a couple months ago because I had thoughts of visiting DLRP again this summer. I am going to Spain next week and will be traveling around Europe for 3 weeks with my family. If they still had Tarzan I would have tried to squeeze in 2 days at DLRP. Alas, no. IMO you only need two days at DLRP. Maybe two and a half. I had three full days and ran out of things to do.
The DRLP setup is much like DLR. Two parks very close together like DL and DCA, and a DTD-like place also very close (I think they call it Disney Village).
Without giving any spoilers - just a heads up - when you finish Phantom Manor (their version of Haunted Mansion) pay close attention at the end before you get out of your doombuggie when the ghost appears. They have a very cool effect you will physically feel. I rode it three times and my first time I thought - OK, this ride is over and the ending is just like DL and MK. I barely noticed the effect. I went back two times to check it out. So just keep your eyes up on the mirror and
feel what happens.
Also, when I was there they had a Good Morning Fantasyland (GMFL) breakfast inside DLP if you stayed onsite at one of the six DLRP hotels - it was free. I did that twice and it was worth it. It is sort of like Magic Morning at DL. You get in early and can ride several Fantasyland rides with short lines.
The DLP castle is my favorite castle of all the Disney parks. Go up inside the castle. Also go
under the castle for a surprise visit to a local - ahem - resident.
Make sure you spend lots of time in Fantasyland. DLP's FL is the best of all Disney parks and very magical. Lots of bridges and water and cool shops.
The best DLRP forum I found was here on DIS. Lots of helpful Europeans who visit DLRP and WDW - many British.
Make sure you spend time on the island in Adventureland - can't remember what it is called - Skull Island? Lots of detail and cool theming and nooks and crannies.
When I was there they were 100% strict with Fastpass. 30 minute windows - not 60 like at DLR, WDW or TDR - and no late FPs accepted.
See the Lion King show at DLP. You need to get reserved tickets in the morning and they have performances in both French and English. LK did not blow me away like Tarzan but it is highly rated and popular.
See the Once Upon a Dreams parade at DLP. After I saw it I had to buy the CD of the music which I have on my iPod.
It is worth seeing the Lights, Motor, Action show at WDS which inspired the LMA show at DHS in WDW. They do it in parallel French/English and it is fun.
Have a magical trip!