6+2 probably means six permanent beds and two fold up beds.. that might be in corridors for example.. so must be folded away in the morning.
Beds on a boat may be much smaller than you used to.. 1.5 foot wide, maybe 2 feet. A double might be 2.5 to 3 foot... Good fun though.
I spent a lot of time on the Shannon as a kid, on my dads 27 foot boat. I think it's very tricky to drive a boat for a beginner, nothing like a car.. you have to cope with waves pushing you.. steer into the waves.. I've been on Lough Derg in a storm, when dad went to refill the petrol tank, mam held the wheel for 30 seconds.. result was we turned side on to the waves, boat was flat bottomed so didn't overturn but did go up on it's side, everything went everywhere.. I was only 7 maybe and the youngest, quite frightening!, he he.
Parking is tricky.. have to go into reverse while moving forward, this can cuase the boat to spin.. to recover takes experience... I'd say a lot of boats are crashed... can be hard to walk along deck while coiling ropes and throwing them accurately to the man on shore.. need people on deck with barge poles 'all hands on deck' etc etc, he he, good fun when the panic is all over..
Navigating the river can also be hard.. have to stay within the markers.. they may be hard to spot.. can't just stay in the middle of the river.. in some cases only 20% of the width at one side is navigable... also have to contend with weeds and stuff clogging up the propellor.. then you'd be drifting helplessly... you have to remember which direction you're going (i.e upstream or downstream) or you'll go on the wrong side of the markers, and maybe run aground.
All in all though it should be good fun.. nothing like waking up on a rocking boat with the waves gently lapping against the side...
Toilet facilities may not be great.. scandal a few years ago where the rental companies were apparently telling people to throw it overboard, not supposed to do that but facilities can be non-existent..
Having said all that it was 20 years I was last down,.. so things may have improved a lot.