You can define long at any distance you like. If you typically ride 5 miles a time (i.e. not much) and every so often will take a 20 mile ride, then that's long. For me, it's something longer than 30. I occasionally will take a 50 or 100 mile, but not all that often.

Which is your first choice bike for a long ride? Is its wheelbase long or short? About how much does it weigh? Does it have fat, cushy tires or narrow bone shattering tires?

I'm seeing an increasing number of people on fat-tired but light bikes, and maybe there's something to that. I'm curious to know how light you can get a randonneur or similar bike, with 700c or 650b tires. Maybe there really is something to this 650b crazy. I've been hesitant to try.