How to reach Verbobonc via console: Open up the game console (this is accomplished by pressing shift+~) Then enter: game.fade_and_teleport(0,0,0,5121,500,500) This will teleport you to Verbobonc. To get back to Hommlet, you might need to employ a similar method: game.fade_and_teleport(0,0,0,5001,620,407) This will teleport you just outside the Welcome Wench Inn. It might be necessary if you're running the old version of Co8, or don't have Verbobonc marked on your map or something else I'm not thinking of which could be cause by teleporting directly to Verbobonc in this fashion. In Co8 5.0.5 it might be redundant.
With the limited number ogf visits you can take to Verbo via various NPC's, the following might help out those in need: Try to rescue the 2 girls on level 1 and the 2 merchants on level 2, one at a time. Each one should give you the option to go to Verbobonc. You can return back to the Hommlet area via the travel agent, if you need to. However, to go back to Verbobonc, go back and resuce the next hapless victim. Rinse and repeat as needed. I initally messed up when I rescued the 2 girsl on level 1 and missed my 2 trips to Verbo. However, I was able to rectify this by rescuing the weapons merchant first and returning him to Verbo. I then went back to the Temple and rescued the armor smith and made the return trip back to Verbo, where I'm ready to take on the new quests. Thankfully, the prisoners are smart enough to stay put until you come back to rescue them. The last thing we need is to resuce one and have the other get upset about being left behind and try to find their own way home. If you've exhausted those options, or messed them up somehow, you can still get to Verbo thru Rufus. He'll need to be in your party and level up a bit before you get the option to travel. Barring the above, you could always go to the console and use the teleport feature. I haven't tried this yet, so if it doesn't work for you it's now my fault! It may be best to go through the one by one rescure scenario and then stay in Verbo until you're completely done with the area. Good Luck all!
Bear in mind the Verbo situation will change: it's already a worldmap location in 5.0.6, and in the future all those prisoner escorts will be washed out. It's just a matter of getting to that point modding-wise; we're still working on fixing up other stuff at present.