OK, if all you want to do is view web pages from your second box on the net while still retaining all your doing with your first, do this.
Create an i-bay for your second box to claim as its own
Create a virtual domain on your first box that is the name of the domain you use for the second box using the above i-bay
From a shell on the first box, mount the location of the website you want to see from the second box to the location of the i-bay on the first box. For example, if the web site on the second box is the primary web site and the name of the i-bay on the first box is website2 then you would type:
mount -t smbfs -o username=admin,password=ADMINPASSWORD //192.168.1.10/primary /home/e-smith/files/ibays/website2
You will have to, of course, replace ADMINPASSWORD with your real password. If you like the results, and want it to happen everytime just add the line to your rc.local file.
However, if you want to use all the other features of the system, you will have to split your internet connection between the two systems. For example, if you have a cable modem connection you would place a hub after the cable modem and connect each box to the hub. One would become your "production" box and one would become your "test bed" box. This kind of division is quite wise when doing test work like this.