Without the add-on FoV, the end of D2:ED is you getting stuck in the crystal and then the cutscenes of Damian and Ygerna, and the Black Ring attacking the fjords. Before the add-on was announced, a few people were a tad peeved about the ending.
FoV is an add-on that continues the story from the end of D2:ED, or you can create a new level 35 character (as you found, with gold to get you started buying equipment). If you go into the custom character setup, you can also possibly access extra skill levels for some skills (that you max) compared to continuing with a D2:ED character).
You should still be able to use Summon Demon in FoV, if you had it in D2:ED. Did you change equipment, and loose that skill bonus, or not re-learn it after unlearning your skills? There are two trainers in the ministry to raise level caps, only one of which would have the Summon Demon spell (or you can return to your battle tower trainer).
After the cutscene where the healer was trying to stop the soldier from burning the undead corpses, you are asked to choose sides. If you side with the healer you get experience points, if you side with the soldier you can leave the immediate area and then return to get the key (for the nearby chest). I tried it both ways, and reloaded a few times at the chest, but got relatively poor random loot (so I reloaded again and took the experience). On the other hand, if you get the key, missing the experience isn't a big deal, since opponents in caves (and the Crow's Nest, which you'll get access to later) respawn, so you can go through a few times if you want more experience.
If you wish to level it helps to delay turning in quests, especially since some opponents don't respawn after you complete one of the main plot quests.
