What the hell is a Senior Sales Engineer (Salesforce.com)? I have a pretty good understanding of what those words mean separately, but as far as I can tell they to not belong together.
They work with the Sales team to give technical support and advice to potential customers before they buy a product. It's not a fun job IMHO unless you are technical and like to travel a lot.
I've done it before. It also involved working with the client on customization since the sales people don't always understand exactly what's possible.
It's fun if you like traveling and interacting with customers. Actually being part of closing a deal is kind of a rush. I imagine it pays well because it's not too easy for the sales guys to find engineers whom they're excited to bring to a meeting.
It can also be a great place to get comfortable dealing with high level business people, Fortune 100 executives, etc... You have to be able to (or learn to) communicate clearly to the super technical folks they bring, and to the CEO who can barely use his e-mail. You get very comfortable speaking in front of a large group, and you learn to think on your feet.
I did it for a few years, before the travel burned me out, and I feel I learned an amazingly amount of useful skills from it. Stuff they can't effectively teach in school and that you can't learn coding in your living room.
Fly home on Friday, fly out on Sunday. I don't know how they do it but I do hear if it's cheaper to fly somewhere else for the weekend (e.g. San Diego vs East Podunk) they'll let you.