International trip planing with parents

I've mentioned in other places, but to recap, I'm sponsoring a trip to Japan for my dad (my nephew is taking him) & I'm taking my mom & sister on my mom's one & only international trip. The goal is to do traveling with our parents (also still planning to get together with M's mom, when that's possible) while that's still an option. It means front loading some of our travel spend in 2027/2028 vs more spread out over the next 10 years. Travel planning for my dad's trip is a bit on hold as we wait for flights to open up, but we will likely book flights over the next month or so. 

Planning/location:

After quite a bit of discussion & researching options, and hitting the balance of seeing some of the things my mom wants to experience, but doing it in a way that works for her & our group, we landed on a very small cruise in May, that allows us to go to some of the (less) touristy destinations.

We will be flying into Athens, spending a day there before we get on the cruise, mostly to ensure there are no travel delays. Then we will visit three Greek islands, including Paros - which was a huge favorite when I was there this summer, & two islands new to me. We will then go to Croatia & I'm very excited to go to Krka National Park, which looks amazing. 

The cruise finishes in Venice, and we will spend 1.5 days there before flying home, and will do a few Venice tourist activities. 

Cost/optimization:

• I booked the cruise through Chase travel, which means I'll get 8x points for the purchase, and also a $250 excursion booking credit per person. I'll share more details on the cruise as we get further along.
• Because the cruise was quite a significant expense (traveling with three is hard, and requires a second room), I really wanted to keep the flights in check. I also had some complicated travel booking (multi city with Athens & Venice) & then on the way home, my mom & sister will be routing through Portland & I'll be returning to San Francisco. The logistics nearly did me in! But, I found some options to use miles for one of the routes, and then found some less expensive economy flights for the return. There were seat booking fees on Lufthansa that added to the overall cost, but I managed to get all of the flights needed (minus the flight from my sister & mom one way from Portland to SFO the night before) for just under $2400, which felt like quite a feat.
• For the hotel in Athens, I booked a Hyatt hotel on points for two nights, for two rooms, and used a Suite Upgrade Award, which will hopefully secure a nicer room. Total cost on that was $0.
• I'm hoping to use Chase Travel points for the hotel in Venice, as Hyatt has limited options there.

In terms of what else I still need to pay for, and how I'm thinking of the budget, I have planned:

• Transit from Athens hotel to the port
• Transit from Venice port to hotel
• Food & activities in Athens & Venice
• Excursions on the cruise. Drinks & tips are included in the cruise, and there is no additional food up charging. 
• Travel insurance
• A one way flight for my sister & mom from Portland to San Francisco, hoping to use miles for this.

I'm new to cruising, so interested to see what this is like! If you have any tips or suggestions, please share!