I ran an ancient Toshiba 320CT Portege in my 60... it's a 10.5" screen... Windows 2000... color.
Good UltraLite Laptop. - Toshiba Portege 320CT (PA1274U-T2A) PC Notebook - Epinions.com
Works just fine hooked up to a Garmin V with Topo maps and others loaded onto the HD. I built a combo cord to power the computer and GPS and also to connect the two... GPS is mounted on a custom mount up above the rearview mirror. I have a front bullbar mounted external antenna too.
(I recently got a big Lowrance unit that speaks to me... better for the road but not as helpful in the woods as the Garmin/laptop combo.