I've never delt with DV cameras files on a PC system before (only on a mac and that was many months ago). However Load your two huge ass dv files in unlead and join them together.
Then make sure you save them in their native DV format without any recompressing.
How download nandub and try to open your combinded DV file. If it opens all is good and keep following the instructions below. If it doesn't you may have to convert your DV file into an AVi file, or download the appropriate codecs to get it to open.
Once it's open in nandub follow the sbc guide found here:
http://doom9.org/sbc_main.htm
Starting from step 5.
------------------------------------------------
Note use the sbc guide to encode the video only.
------------------------------------------------
As for the audio simply open your combined DV flie in unlead or nandub and save the audio separetly as a .wav file.
Once you have the .wav file use razor lame + lame to encode it as a vbr mp3 file.
Lame can be found here:
http://doom9.org/Soft21/Files/Audio/lame-3.91.zip
Razor Lame GUI can be found here:
http://doom9.org/Soft21/Files/Audio/razorlame114.zip
Make sure you set razor lame to optimize for quality, with a quality setting of nine and i would recomend your bitrate settings to be set arround min bit rate 96 max bitrate 192 for a single disc rip.
------------------------------
Note: there's probably many different ways of encoding the audio but the method above works for me.
------------------------------
Hope that helps.