personally, blarneys isn't my favorite... I've been there maybe a handful of times in my twenty something years of boating on the chain.
i helped with two "local" bachelor party's where we all went and did something before (one of them we went to K1 speed, then Lou Malnati's, then got up here... the other, alrington horse track, tracks in cary for food, then got up here...)
what we did for those two, was went on the previous (sober-ish) events, then got up to the chain area... we rented the party boat that leaves snuggery or freddies for 3-4 hours each time (can't remember exactly) and it was around $30 a person or so if i remember right... BYOB. you can have them setup with a drink package and a bartender but i know how to pour rum, whiskey, and vodka with the best of them.... so quite a few handles, a bunch of cases of beers on roll on coolers and we were good to go.
we met at the snuggery around 5pm, and had the boat scheduled to leave around 6:30pm iirc... i think i also told everyone boat was leaving at 6pm to make sure everyone got there in time. then from there we left snuggery and boated up the river, around pistakee and meyers bay, and then to freddies... had a few drinks at freddies, hopped back on the boat and hit up cabana's for more beverages... got back on the boat and headed back down river to snuggery to continue the debauchery.
if i were you... and with you guys not being from the area, id want to stay up here or get a bus/limo/van/ride back to wherever everyone's from.
i mean you could get start and finish at snuggery and stay at the hampton inn in mchenry and just get a taxi back to there when you want.
orrrrr... do it this way.
have everyone meet at freddies at 5pm or whenever and eat some dinner (freddies is REALLY easy for groups to eat at because you get your own food yourself... waitresses don't bring it to you), have the boat leave from there at 630-7pm, cruise around, hit up snuggery down river for a drink or three then head back north... hit the wave in johnsburg or china bar for another beverage or two and a decent atmosphere, if time allows, hit cabana's as well and continue on your cruise... then wind up back at freddies which is open until 2am for your drunken debauchery to continue.
link to that boat:
Rockin The Chain - Party Boat Cruises On the Chain O'Lakes & Fox River
you can of course do the blarney's shuttle, but then you're restricted to going to blarneys... from port of blarney... maybe they will have a good band that night and maybe not.... additionally once you get back to port o blarney, you're kind of in no-mands-land even moreso than most places up here, as another near bar, restaurant, or hotel, aren't really all that close.