This reminds me of the Gentoo fans who thought that they were somehow more "in control" of their machines just because they were copying/pasting commands from the Gentoo forums and building Gentoo from source. It was an exercise in yak shaving, just as an offline installation when you have access to a broadband connection is and just as configuring a dial-up connection knowing that you're switching to broadband Internet anyway is. Taken to the extreme, I suppose you could get a printout of all the software you intend to install and start transcribing. :)

 

I don't know if you realize that you have spent more time talking/writing about this than it would have to download and install Debian. If you are at your friend's place and your friend has a broadband connection, you'll have Debian running in about 20 minutes with a reasonable network connection. Installing this way does not preclude you from using a dial-up connection to update later. In fact, if you install via a DVD, you're going to have to change /etc/apt/sources.list to point to the online repos that your machine should fetch from when you connect via dial-up. Otherwise, it will check for updates on the DVD. If you install using your broadband connection, you won't have to change a thing in sources.list to update later when or if you get dial-up working.

If I were in your shoes, I would download the Debian netinstall CD, which is just over 300M. That is small enough that you can even do that over your dial-up connection. I would boot from the netinstall image and install away while you have a broadband connection. Subsequent updates generally won't be that big so if you get dial-up working, you'll be able to do the updates when you connect. I say "if you get it working" because I don't remember what type of modem you're starting with. If you have an exernal modem, you should be fine. Internal modems are dicier. There were many that were WinModems and those wouldn't work 20 years ago when dial-up was commonly used. In those days, I used to use wvdial. I see that it's still available in Debian <https://wiki.debian.org/Wvdial>.