Itinerary help Malta + Sicily or Montenegro ?

Well, no wrong choices here - just the problem of deciding. :)

Malta and Sicily seem to pair well together and are on my list for the future. The Montenegran coast is absolutely gorgeous. It would definitely pair well with Croatia but it sounds like you have been. You could consider Albania with Montenegro, as well. It is a mix of beautiful coast and gorgeous historical towns and pretty countryside. My vote would be Montenegro and Albania, if you are up for something a little different than most people.

All of the above for Malta and Sicily. It wouldn’t be hard to spend two weeks in either. In Malta, Valletta gives you an excellent base, except perhaps for hiking, but beach, bars and history, no problem. Sicily has beaches, but in my view, not a lot of great ones. No info on hiking here, either. It would be easier for us to give you some opinions on your planning if we knew when you plan to go, what part of Sicily you are considering, and how long you’d like to spend in each place. There are lots of trip reports on Sicily and Malta; you might want to narrow down your options by starting there. In Malta, 14 days might be a little long, unless you want to build in some serious beach and bars time or want to delve deep into history. Montenegro has a different vibe. There’s history and hiking, but I’d say that the beaches and bars are less compelling.

...beach, bars, history, and some hiking.

We like Montenegro, but Malta and Sicily would be our first choice. They have a variety of all of the things you're looking far.

I spent 8 days in Malta earlier this year. Never found a beach that vould compare with Montenegro. In fact Malta hasn't got many beaches. Here is an idea:
https://www.maltauncovered.com/travel-guide/best-beaches/ Hiking? Not a lot in Malta set up for that. We tried a bit. History, architecture, party scenes all very good. I liked Malta, just doesn't jive with your list of interests tò well.

Montenegro checks all your boxes from beach to mountain hikes.

Sicily? Never been. Don't know.

Also think about Albania.

We enjoy party scene but just not everyday drinking. most of our trips have included a big city+ historical small town + beaches.
Interests: Partying (not everyday), excursions, beaches, history, hiking/ national parks, road trip and good food.

I also went back and read your OP for your Croatia trip. Montenegro and Albania - a week each - would give you all the things you have listed.
Montenegro has gorgeous beaches and by just walking to the beach and buying a $10 (or less) ticket you can quickly be at even more beautiful and secluded beaches. They have beaches down well. Places like Budva appear to have plenty of party opportunities. There is also Durmitor National Park if you want mountains, views, and hiking. Plenty of history, as well. Driving is not as easy as Croatia but it’s doable.

Then move on south to Albania. For serious hiking, try Theth to Valbona (or the opposite). Ride the Komani Lake Ferry. Tirana is surprising - plenty to see and do for a somewhat small easy to navigate capitol. Then there are Berat and Girokastra for history and culture. And so many beaches, it will be hard to choose. Albania would be an adventure. I loved my 2 weeks there.

Can’t take a car from one to the other, though. So it would require 2 car rentals and the bus from country to,country.

It is also extremely easy to pair Albania with northern Greece (think Corfu).

And Malta is a purr party island so maybe not your cup of tea. What TexasTM said. Ditto

I think 2 weeks would be awfully short for Sicily + Malta; it's about the minimum time I recommend for Sicily alone if folks are going to rent a car. It takes a bit longer to hit the highlights via public transportation.

We visited Montenegro and Albania last summer and it has absolutely everything you're looking for. We did five days in each with another five days in Corfu afterwards. We enjoyed it all but it was fast paced and we ended up missing a few places we would have liked to visit in Montenegro and Albania. Here's our 10 day itinerary that might help. https://sunsetsandrollercoasters.com/balkans-itinerary-10-days-in-montenegro-albania/ If looking to party, spend more time in Budva than we did.

How did you travel between Montenegro and Albania? Car? Bus? Train? Flight?

Maybe I can work out some logistics.

I did them on separate trips, so didn’t go from one to the other. Bus is your best bet, unless you hire a driver, which isn’t a bad idea. Things like that are still so much cheaper in both countries.

If you decide you want someone to help you maximize your time in Montenegro and get you to Albania, I would suggest talking to Dijana Krkotic at Doclea Travel, [email protected], www.docleatravel.com. Divided several ways, her fee would be MORE than reasonable. She planned my two weeks and captured how I like to travel perfectly.
:My trip report

The hardest part about Albania was figuring out the minivan process city to city, since I didn’t want to drive; but it works. Let me know if you want a recommendation for a company for day tours (has a base in both Tirana and Berat). My trip report.