Spent most of yesterday defending a keep in the Shadowlands - mostly against small groups that weren't too hard to deal with for a handful of players.
We had 2 large groups of around 20-40 blood sucking destruction scum attack first in the morning then again later in the evening.
We had plenty of siege eq to defend with and a decent engineer on hand to man the cannons. We kept the oil flowing until the idea penetrated their thick skills to attack the cauldron above the gate - with only a handful of people defending it was hard to keep things repaired until reinforcements arrived. Messengers were dispatched while we kept them at bay and help arrived before the main gate was taken. A handful stayed on the ground floor, elven archers on the stairwell raining blows from above before most retreated to the first floor to take up positions on and around the stairwells.
We found it handy to keep the oil falling even when the gate had been breached - a few retreating to heal were spirited back to their camps swiftly - others were damaged enough to delay an attack giving us a brief respite.
Gunners placed their cannons on ledges above the lower-stairwell which helped a lot in keeping the healers and ranged support at bay - making it hard for their tanks to break through without support. Those that did ran for the outer wall allowing them to pick off small groups that ran after them. Keeping a few small groups at both entrances to the outer wall allowed them to pin the tank between them and take them out in quick time. We kept people on the guns - so any incoming support they had either met a swift death or were dealt enough dmg to approach with caution. After 15 mins or so the keep door reset and those inside were trapped. Again the oil helped keep those attempting to take the door again from the outside. The number of attackers inside the keep dwindled and they attempted to break the keep door from the inside to allow reinforcements to assist. Their focus now shifted we were able to slip down the stairwell and smear the inside of the door with their bile.
Use the npc's if you're in a small group - lure the hostiles out and then assist them - you'll survive, they won't and you'll be around to stop the keep falling.
If somebody makes it to the outer wall- it's better to defend the stairwell if you don't have enough support. You can take out the hovering hostile when they come into view. Small groups pinning them from both side is more effective than a couple of solos chasing. If they die you have less defenders against the mob.
You can hover at the top of the stairwell down and deal dmg pretty effectively and it stops the entrance to the stairwell down from getting congested - allowing your tank to work more effectively.
Don't let your guns go unmanned if you can help it and let people know how to repair them. If the defending eq is under atk it's going to take more than 1 person to repair them. Don't be afraid to ask for help or to let people know.
If you like playing with keeps - keep siege eq handy - I always have 2 items of all 3 types in my inv - something's always gonna break and having a spare can save the day.
One last tip - if you pop your clogs and rush back to help - keep your ear against the back-door before entering. If the lower lvl is swarming with vermin - you won't last long on entering - better to wait or ask for a diversion. Getting yourself killed won't help and it saves the long run back.
We managed to maintain control of the keep both times and in each case we were out-numbered and out-leveled!