I'm up to about L26, rep 31, and have managed to collect two castle invitations. I did a -lot- of lawnmowing in the main part of Ferol, cleared out that map except for the castle, and have done some quests in Verdistis. Currently I'm exploring the Verdistis sewers. I haven't been to the Dark Forest at all yet.

When should I go ahead and use the castle invitation? I know from consulting a walkthrough that there are going to be rep consequences, how high should I look to build rep and level up before landing myself in the soup? Will I not be able to finish off some Verdistis/Dark Forest quests later if I go to Stormfist now?

Finally, I'm running a mage and don't have a very high strength, even with equipment boosts, leading to frequent teleporter stone trips to my storage facility to leave items. Should I do a massive selloff of stored items before going to the castle? I looted a bunch of golden urns from the starter dungeon for storage and I've been slow to sell things, I've got hundreds of items stored.

I usually clear out the main Rivertown map and Verdistis (quests and enemies) before using the invitation.

The rep you lose is simply rep you gained upon entering, IIRC. If not, the loss is minimal and won't hurt you.

Entering the castle will take your teleporter stones and railroad you into a longish dungeon sequence, so sell/store everything you don't need on you. No harm in leaving stored items as they are.

Entering the castle won't stop you from completing anything else (all quests everywhere will be waiting for you when you come back), you basically just have to clear up everything in the castle, do a dungeon, and then you are free to go as you wish.

To regain your teleporter stones, however, you will have to sneak back in the castle through the sewers, rescue Zandalor, and then clear a medium sized dungeon room.

So it's best to be ready to commit to all of the above before accepting the invitation. Level 26 seems high enough.

Thanks, that clears all that up, I'll finish questing in Verdistis and head on over then.

You end up with a net loss of 5 rep I think, but that's largely irrelevant as rep doesn't really make much difference. You just need enough that people will still talk to you.

Personally I always put the castle off until I'm completely done with the main Ferol map, and then I work on getting my teleporter stones back IMMEDIATELY afterwards. DD without teleporter stones is no fun at all :(

It is a 5 point net loss of reputation. Most of the traders you deal with should be at or near 100% anyway. If you clear the Rivertown sewers before going to the castle, it will be easier than doing it after (since you'll have your teleporter stones). I did that and cleared most of the first map and Verdistis before going to the castle.

To prevent yourself from getting encumbered, you can stash everything you don't need (that you loot inside the castle) in a chest, and toss it out the front gate to get later. After that, you can always stash stuff in a barrel and put a note on the map to come back for later.