This suggestion is for the next time you load your OS.
install DOS on a clean hdd using DOSs FDISK to create
the desired partition size, leaving the rest of the drive
un-partitioned. once the DOS installation is completed,
simply reboot with the XP cd in the tray. Use XPs fdisk manager to
create a partition <E:>. It's going to be <E:> because <C:> exists and
<D:> will be the CD-ROM Drive.
Once the XP installation is complete you have two choices:
1) leave everything alone
    or
2) change the drive letter of the CD-ROM to something past <F:>,
   this can be done in the Disk Management section of the Storage
   section of the Computer Management console.
At the following link: http://www.jsifaq.com/sube/tip2000/rh2011.htm
is an excellent method to change the DOS partition to <Z:> and change
the XP partition letter to <C:> Later you can go back and change the
CD-ROM drive back to <D:>.

This way XP is on your C drive, D is the CD, and DOS in on Z, Nice and
clean I would say.

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Or you could simply install MS-DOS in a Virtual PC. I have
MS-DOS v6.22 running in a Virtual PC quite successfully.
Use the following link to locate the DOS nic driver.
http://www.essjae.com/VPC/virtual_pc_downloads.htm

I still love to have DOS around for all the old stuff I refuse
to just throw away.
It runs a NETx and a VLM client very well, though I just
use FShare instead for  network mappings.  

Now to answer your question: "Will it be straightforward
to run........"            I really don't know, I'm an old DOS guy,
never needed a sound card or a mouse.......so I can't tell you if they
will work or not in a VirtualPC.     But for me MS-DOS in a virtual PC
will run ALL of my old apps just fine including the two NetWare
clients.

You are not obligated to partition your hard disk to use Virtual PC.
Instead, you can create a virtual hard drive with the Virtual Disk Wizard
and attach it to the virtual machine that you will create.  This will look
like an ordinary file to your host (WinXP) but will look like a true hard
disk to the guest (or the VM).  Take a look at the documentation before
starting repartioning your hard drive, as it is usually an unneccessary step
for using VPC : it's an emulation software, so it will emulate the necessary
hard disks as well.  You can even run Partition Magic on them.

If will be straigthforward to run DOS under VPC but some programs may not
run well on the underlying Pentium.  (Some of them may only run on a true
386.  This is especially true for games and software with copy protection
schemes.)

You can also give a try to DosBox 6.0: it's free and work very well for many
old programs and games, but it's much more slower than VPC :
http://dosbox.sourceforge.net/news.php?show_news=1

If you have the full version of Connectix VPC 5.2, instead of the trial
version or MS VPC2004, then you can find a virtual hard disk preformated
with PC-DOS: "PC DOS 2000.vhd" in your installation.

As stated in the first answer, you will need to download the NIC driver if
you want to access your network with DOS under VPC.

S. L.