Advice needed for Navigation

[tallin32]

Greetings.

OK, here's the issue I'm having (and I hope I'm posting in the right thread). After reading about the Iraq war vet who was able to play World of Warcraft without sight, and myself being both a software engineer and blind, it occurred to me that, if a bot can play World of Warcraft with no human intelligence behind it, there doesn't seem a reason that something couldn't run in- or out-of-process to speak texts, give object info, etc. as needed (let's forego questions like why a blind person would want to play World of Warcraft, how a blind person can program a computer, or how a blind person knows when to stop wiping (Google this. It's come up.), as I have neither time nor inclination to answer them here).
One thing that's got me puzzled though is navigation. Drawing on my own experience, if I were navigating in an environment, I only need to know information a certain distance ahead of me (if I'm walking from the light rail station to my office, an open manhole 15 miles off isn't going to mean much to me). If I were writing an AI, I'd obviously use NavMeshes to determine where it's safe to walk--but I'm also handling movement if I do that. For this project, I'm assuming that the player is still going to maintain a certain amount of control over … um … the player, and will thus only need to know whether or not, if the current trajectory is maintained, Something Bad™ will happen. Will I need to distribute NavMeshes with this, or can I do this through some other means? Am I more concerned than I need to be about the added bloat of nav data?

[Jadd]

Traceline could work. It's basically a client-side line-of-sight check between two positions. Just check a few yards ahead of you to see if there is a sudden drop. Of course nav-mesh would be much more accurate.

[tallin32]

Traceline could work. It's basically a client-side line-of-sight check between two positions. Just check a few yards ahead of you to see if there is a sudden drop. Of course nav-mesh would be much more accurate.

Now that I think of it, NavMesh might be better anyway, because I'd want to check in a 45(ish?) degree arc, and do the check a variable distance ahead based on the player's speed, turning radius, and ... selected mount, if any, by the looks of things.
Incidentally--unless I'm completely misreading some other threads on here, does this mean I'll have to generate a mesh for every possible mount the player is likely to use?
Also, would TraceLine as a quick and dirty fix be able to give me the type of terrain I'm walking on (road, snow, etc.)? I've done a search on the threads and either I'm missing something obvious due to panic-induced reasons below, or documentation on TraceLine is sparse. See, I recently spent the longest 7 minutes of my life actually having to wait for a player to come and find me and guide me to Ironforge—and if that's the sort of way people assume blindness works in the real world, no bloody wonder some people fear it worse than death. Good GOD but it's an unnerving feeling.