Do long haul domestic flights work well with large aircraft?

In real life Air France operates several long haul flights from its Paris Orly hub to Saint Denis, Martinique, Guadeloupe, and Mauritius using several large aircraft like the Boeing 777-300ER and in the past the Boeing 747-400. In AS these airports have usually between 3-5 bars of passenger demand and usually only 1 bar for cargo demand. Do these long haul domestic flights with large aircraft work in AS? 

Examples Include:

ORY-CAY Boeing 777-200ER

ORY-PTP Boeing 747-400

ORY-FDF Boeing 777-300ER

I've never tried these routes before, but it seems like the airlines that have the most success with them operate hubs with 500 departures at minimum. A smaller widebody like a 787-8 would likely suit the route more, especially if the demand isn't initially that high.

You will need a very good domestic network with many connections in France before starting these flights to the French Carribean destinations. Then the choice of aircraft is dependend on server and the used market / availability of longhaul planes.

From ORY to French Caribbean, you can also use the narrowbodies:

A320neo HVY

B737-900ER HGW all versions

A319-LR

B73G-ER

CS-100

As this is a long haul fight, you should use at least comfort plus seats in Y. All mentioned aircraft work well on this route.

You will need to provide a good onboard service and charge more than default to make it work on the narrowbodies but it's not that difficult.

Yeah, Mauritius has a place very close to my heart so of course that I fly there. The routes works ok but I have a partner there, I operate an A320. In real life Emirates operate two daily A380 flights on DXB-MRU route and trust me the A380 looks like a giant at such a small and sleepy airport. On Stapleton a player operates three daily 747s and 2 daily 757s on the DEL-MRU route.

yes, it works....on a new Server with B 787-9 for example without Feeder Network...

In real life Air France operates several long haul flights from its Paris Orly hub to Saint Denis, Martinique, Guadeloupe, and Mauritius using several large aircraft like the Boeing 777-300ER and in the past the Boeing 747-400. In AS these airports have usually between 3-5 bars of passenger demand and usually only 1 bar for cargo demand. Do these long haul domestic flights with large aircraft work in AS? 

Examples Include:

ORY-CAY Boeing 777-200ER

ORY-PTP Boeing 747-400

ORY-FDF Boeing 777-300ER

the Demand is there - it's just distributed differently.

Let's say in real life there is about 4 daily flights between Mainland France and La Reunion. Two are operated by Air France 777, maybe one by Corsair in a 747 and one with a Air Austal 787. So in total that leaves us with around 1000 -1500 daily passengers that will be travelling between RUN airport and either CDG or ORY.

What Airlinesim does , it takes these 1500 passengers and devides them equally among all airports in both the Reunion and Mainland France region. This means that not all 1500 passengers will want to Travel between Paris and Reunion but maybe 500 or 600 will acutally want to travel to another airport in Mainland France like LYS, MRS or SXB. You can now try to rely on a direct flight between Paris and Reunion using a smaller aircraft (like the CS1) or build up a domestic feeder network.