The UNIX space should be pretty accessible as far as sysadmin goes since so much of it is command-line. You might need to get a certification in order to break in to the field, which has its own accessibility challenges.

I did freelance computer tech stuff briefly (a matter of months) before deciding it just wasn't for me. Unfortunately, you just can't get or do any job that requires you travel. Your best options are:

1. Start your own business. Have customers bring broken computers/laptops/whatever in for repair, have them leave it with you, and call them to pick it up when it's fixed. If you need to read BIOS screens or whatever, you can use OCR with an app like KNFB reader. However, this is painful and slow, and your time might be better spent getting someone else to read those screens for you. If you're fixing a broken OS installation or whatever, your best bet is to just pull the drive and troubleshoot it that way, rather than trying to boot a known broken system and OCR the errors. Unfortunately, this does mean doing a lot of dealing with customers. If you can get it, you might be happier with a job in the back of a small, local computer shop. That way, someone else can deal with customers and you just work in the back. Also, there are people around to assist you if you really need it. I could never get this kind of work myself, though.

2. Go into Gray collar software development work. These days, with frameworks like Drupal and Wordpress, most web development doesn't involve any programming at all. Most of your time will be spent creating websites via the GUI, training customers on how to add/change content on the website you've created, keeping the website software up to date, and maintaining the hosting environment. Unfortunately, if one of the web servers goes down, you still have an extreme risk of people calling you in the middle of the night to yell at you. Speaking from experience, it's way worse when you were sound asleep. Also, the small local businesses who tend to hire one or two-person web development shops tend to be, let's say, reluctant to pay bills on-time. If you've got some partners who can handle dealing with customers, and getting the bills paid, leaving you to do the technical stuff, this might be work you'd enjoy. If not, though, you'll find it just as stressful as working the phones.

I worked in a quality assurance testing lab for an OEM between 2002 and 2004 where I had to assemble computers according to provided specifications, benchmark them, report the results to the commercial department, and create customized Windows installation ISOs with the OEM's branding and all the required drivers pre-installed. At the time I was only legally blind and honestly I doubt I'd be capable of doing it fully blind.

I was a freelance technician at first (through connections with my uncle, who did telecom in the hotel industry). A lot of the work was stuff I could do at home before/after (like basic setup for a new system before adding to their domain/etc). DVR could have helped with transportation at the time, but it wasn't regular enough work and my other job (retail) was walking distance.

I went back to school for an IT degree and worked at the campus help desk. Only problem there was using screen magnifier with multiple monitors, which I eventually got the hang of using together.

I did have a few interview post-college that wanted travelling techs; they never got anywhere (though again, DVR would have helped).

I eventually ended up at another place that did phone support, where travel wasn't necessary. Working a later shift meant a lot of calls were maintenance-type issues where they'd call, get me connected, and then let me go to do what I needed. The company even started doing some telecommuting from home when winters were getting too bad out.

I don't know how local repair shops would work, but you could even do a home-based business for drop-off service, which wouldn't require transportation, either.