Since your VHS tapes have no copy protection on them, the easiest method would be to get a combination machine with both VHS and DVD built in.
Something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16882116136&nm_mc=OTC-pr1c3grabb3r&cm_mmc=OTC-pr1c3grabb3r-_-DVD+Recorder-_-Toshiba-_-82116136 Not necessarily this particular one, just using it as an example. The process is fairly simple and the instructions in the manual should be sufficient to get you started. I don't believe it has to be hooked up to a tv to transfer from one format to the other.
The 8mm tapes are beyond my experience I'm afraid. These are 8mm camcorder tape? If so, you'll need something to play them and hook into the dvd recorder.