I cannot figure out who to fly long routes. Obviously I will need aircraft capable of making the flight however it doesn't even appear to be an option?
You'll have to give more information on exactly what problem you are running into as it's not clear. Sometimes you will get a warning that you have no aircraft capable of flying the route but you can still select options from further down the drop-down list. For VERY long routes (and depending on the time period) there might actually be NO aircraft capable. You can add technical stops (for fuel) if you like. Is that something you've tried? You should pretty much be able to fly between any two points on the globe, even in the pre-jet times, unless very short runways are the issue. PM me if you like.
another thing to consider: if the roundtrip takes more than ~22 hours, you probably need to make some creative scheduling. see the "7 day scheduling tutorial" for that.
https://www.airwaysim.com/forum/index.php/topic,71633.50.html