We definitely need some tactics.
All those tents on the other side of the bridge will send reinforcements.
The dragon (Ozzyrenndrrion, I hope!) will be difficult to pin down, and probably only within melee range when he is tearing us apart with claws and bites. His breath weapon will be difficult to avoid.
So, on our side of the bridge, we can expect issues with 2 archers and a hell hound. That leaves 2 archers and a hell hound on the other side (the hound will most likely close on us).
Plus whatever reinforcements come (and they will, knowing this module -- each round).
The archers won't leave their tower positions, so either we take them down at distance, or run up the stairs to each one (not a good tactical move on our part).
My breath weapon is now able to do 6d6 (when I use a 3rd level spell, and it does double damage to those hell hounds!), so that will help take things down quicker when they are grouped together.
I can probably put the acid resistance on another of us (leaving me with 2 3rd level slots for breath) -- most likely candidate would be Kirrg (Jonathan has more HP, and Duroin has evasion)
This will be a ranged heavy combat at times.....
That dragon in the picture looks HUGE.