Friendly biker and snakes of unusual size

I was walking/jogging along the median side of a two-lane road (reminded me of Old Bridge Rd near Smoketown Rd in Lake Ridge), when a woman, perhaps in her sixties or seventies, came up behind me on a bicycle. Instead of cutting around and passing me, or at the very least signaling her presence, she instead crept up next to me, between me and the median, until we were side by side, and she kept pace with me.

I was annoyed, and I asked her why she hadn't just gone by on the other side. She seemed a little annoyed too, but she was really trying to engage in conversation with me while riding along -- probably just trying to be social, whereas I don't go out walking or jogging or biking expecting to end up in a social encounter with a stranger.

We had turned left into a sparsely built, hilly housing area with plenty of trees around. We ended up chit-chatting a little bit, as we went down the sidewalk alongside the winding street/hill. I had already had one or two songs (sung by John Flansburgh) running through my head before we met, and then something she said made me think of yet another Flansburgh song, and I had to force myself not to break into song (figuring it would be kind of antisocial to do so).

We came to a bend in the street (the sidewalk had now ended, and the street was unpainted asphalt), where the street hooked almost 90° to the left, passed alongside the front yard of a single family home, then hooked around 180° and continued down the hill.

Standing at the end of the driveway to the house was a young, vaguely punky woman in her twenties, with brown hair. We both seemed to recognize each other, though neither of us seemed really sure where we could have known each other from. So we said "hi" to each other and looked at each other for a moment before I continued on. Besides the initial confusion, she seemed to have a bemused and self-satisfied expression on her face.

In the stretch of grass delimited by the curved street, there was a single round deciduous tree with a small animal standing on one of its lower branches. Below the tree, a giant snake (at least ten feet long, and perhaps six inches in diameter) came creeping up, and then suddenly sprang up from the ground and swallowed the animal in what seemed to be slow motion. I was pretty sure the snake belonged to the girl living here.

The last thing I recall before waking up was that I had gone a little further down the street/hill, and was now either floating or being held up by a burly man, three or four feet off the ground, and a different snake of identical proportions was lurking on the ground below. I had every suspicion that it was going to go for my foot.