Lost in the Woods

The last week of these posts have been rather scattershot. Partly, I've been concerned with tying up loose ends, looking back over what I've put out to find as many loose threads as I can and pull the ones with any relevance back into the weaving of the adventure narrative. Some of that I've started, but I'm still unsure of the details I want to bring in.
My thought at this point (in adventure terms) is for the party to make their way across, and up through the swampy volcanic ooze deadening this face of the volcano. By doing so, they avoid the obvious defensive triggers that the dragon has guarding approach to his lair. It was always something I intended, but kept putting off by thinking "it's so far down the line I don't need to think about it yet." Except that, now, it is not so far down the line.
A red dragon would protect its lair, making it difficult for anyone to approach without alerting the dragon to their presence. I wanted to create a situation where the lair effects could be felt and have to be dealt with that would be separate from a direct encounter with the dragon (only as a means of putting that off and exploring the idea of lair effects). I also wanted to have a lair of kobolds serving the dragon, with the party reaching the dragon lair through them.
A part of this is straight Hobbit, in that they are going in through a back door, but it was also key to shift that up. I didn't want the back door to be an obvious route, or an undefended one. To me, that meant an approach across difficult terrain and through an inhabited cave system. The path through the kobold warren could be a straight-ahead slaughter, or the party may decide to use stealth measures to slip past. Either could be fun to play. Given that the party is greater than 8th level entering the warren, it should be easier for them to put the kobolds all to sleep rather than have to kill them.
The swamp seemed like an interesting area. I envision a hillside with poisonous pools and fumes, streams of heated sludge, and an odd mixture of water, mud, and lava oozing down out of the mountain like a seeping wound. This, along with the regional lair effects of the dragon, would make this a challenging area to cross, independent of any creatures.
Later, I thought about using some kind of creature, and settled on the slaad. They can be a nasty creature, and the variety of colors offer a tiered challenge threat. The green slaad stone found in the giant stronghold is a late addition, so I don't know how I want to use it yet.
This just brings me back to the opening of this entry, and the fact that I don't know what the end game is yet. I think I still need to work on some of the backstory in order to improve motivations for going through such hostile terrain to face a dragon. It was a nice goal to dangle to keep saying "go forward" for much of the journey, but now, it is more than a dangling carrot, it is the adventure. And a dragon quest deserves to be done well.