This was also important to me when I was considering areas to live. The only real places where I see people consistently walk/bike/take alternate forms of transport (that actually are effective) is in what is called the Zipper and through uptown. The zipper ranges from East Nob Hill (Ridgecrest etc) west all the way to the river, but I would focus in East Nob Hill / Ridgecrest. Here you will find less rentals than throughout the University area/Downtown. If you find that you do not want to be too close to Central Ave. venture north into the North Campus/Altura park area near i-40/Carlisle. This is such a fabulous gem that sits nestled in what I would consider one of the most convenient locations in Albuquerque.
If you venture up to Uptown, you will be limited to a somewhat small radius around the Louisiana Corridor. This is between Washington-Louisiana from Lomas to Menaul.
A great tool to get an idea of areas/prices is to look at this list. All of it is broken down by geographical neighborhoods and sorted by price. Take a look and see if this helps.
I'd be glad to help if you need anything else! Good Luck! Maybe we'll run into eachother someday on foot!
I think all of the top dozen or so are great, and you would like, but I especially like Nob Hill, Inez, Uptown, and Mark Twain for walkability. You will also find it a wise investment, convenient, and good quality of life, if you aim for areas between UNM and Uptown. It would be my pleasure to send you some hand selected homes to consider that will give you a good sense of values and styles, just let me know. Send me any other questions and I will gladly provide you plenty of good information. If you are searching online/remotely, send me an email and I will send you some amazing tools I've developed (pdf's and links) to make searching online much easier and much more effective. Happy house hunting Allene!