We still haven't finished a game....seems to take a long time, maybe because we don't know the rules well yet.  Can you, for example, double back to a sea location? 

No, he may not. If you cross-check the rules (pag. 10, first column, point 3), it is stated than Dracula may not use any of his powers while at sea:

"3. Dracula cannot use any of his Powers while at sea. He is weakened while crossing running water and cannot call upon his most potent abilities. This effectively restricts him from backtracking or staying in place at sea"

So no double back, sorry! As far as the game length is concerned.. well, usually the first games are always a little longer, since you have to get all the rules. Usually a "normal" game (I mean, no bad luck for Dracula or the Hunters) takes 2-3 hours to be completed

I think he might've been talking about Sea-Land-Double Back to Sea scenario. Dracula has landed, so can once again use his Powers.

Uops! Sorry, I missed the point. Yeah, no probs to double back a sea zone from the port you are in!

Yeah, that's how it happened:  I had to double back from a port to a sea location, since otherwise I wouldn't be able to move.  It was also a port location that I'd hidden in last turn...actually, this brings me to another question:   several turns later, the hunters played a card which allowed them to reveal my oldest location, which was the "hide" card.  My location (Cagliari) had just dropped off the end of the board.  Was I obliged to tell them what the location was, or just to let them know that I had hidden in a location for an extra turn?  Thanks, by the way, for the earlier answer!   

If I understand correctly your question, you have the Hide card as a sixth card on your trail. This is something that can never happen. Let's say you're in Venice and in the following round you played Hide. As soon as the location card (Venice) drops off your Track, then you have to reveal the Hide card, and even this card drops off the Trail.

Whoops! Missed that rule.  Thanks:  I guess it'll take a few playthroughs.   

When the location you were hiding in drops off the trail, you must reveal and remove the Hide card as well, as Julia said.  However, if memory serves me there are still ways that a location can be revealed which ends up being the Hide card (while it and your location are still on the trail.)  IIRC - and it has been a long time since I played Fury - in that case you are only required to reveal the Hide card.  So the hunters end up knowing you're laying low, but they may not know exactly where.

Someone might want to double check that I'm not imagining things though, as I say it has been a long time.

Steve, you're definitely right. An example for this is the following FAQ:

Q: What if Dracula’s Trail consist of only one location card, then Dracula plays Hide, and then a Hunter plays Newspaper Reports?
A: Newspaper Reports cannot reveal Dracula’s current location. To prove that the oldest card in his Trail is his current location and therefore cannot be revealed, the Dracula player should reveal the Hide card instead.

A tricker situation could be as follows, if memory serves:

When Hypnotism hits, you (Dracula player) Sensational Press your current location then Hide. This should prevent your location from being revealed other than giving away that you are hiding in an unrevealed location. Haven't played in years and don't have the game in front of me, but this should fly.

Julia said:

When you Double Back to a Sea Zone (provided that I'm in a port by it) I have to pay one blood for the embarking, right? Only in this way it can be considered a legal move I think...

Byga said:

yes, you still have to pay blood for starting a new sea trip.