I speak as a NRP who lives around 1:30 hours away from my 3 year old dd and her mum.
Practically, being separated with kids is obviously not ideal, and it results in inconvenience for the child. A sad fact.
For dd, in my opinion it works better if she's down at mine for a decent amount of time. I pick her up on a Saturday morning and bring her back on a Monday lunchtime. DD at least has time to settle then. And my XP makes sure there aren't any classes on Monday am.
Your XP driving to-and-fro in the same day sounds awful. It may end up him having longer , less frequent visits when she's older.
If I drive with dd she tends to nod off for an hour or so which is great until she wakes up and decides she wants to get out. Hence it's well worth while having a mid journey stop planned. a park usually works.
Mostly though I get the train with her. A few books, crayons, packed lunch etc usually gives us enough to do. And my dd loves being around people so she gets a chance to turn on the charm.
Emotionally, for your dd, your enthusiasm and reassurance for her visit to dad's is pretty key IMO. If you're anxious about it she will be too. The first overnight my dd had at mine her mum came along too. After that mum stayed at home. The first couple of visits involved a bit more reassurance and hugs, but after that she was / is fine. She knows she'll be going home to mums, and she loves it at mine.
As for birthday parties and such. I think the crux of those is how well you get on with your XP and how flexible you both are. My dd had a b'day party to go to recently on one of my weekends with her. I didn't want her to miss it so I visited her at her mums that weekend so that she could toddle along. However if my XP wasn't open to making more time for me to have with DD I'd be much less relaxed about it. And at some point I'm sure she'll miss the odd b'day party when they ramp up in number.
My XP, and a lot of others, appreciate the time they get to themselves.
good luck !