Hooking up a laptop in a semi tractor

My husband would like to take a laptop (not purchased yet) in his semi with him. What are the different ways he can hook one up and what is needed in each case. What is the best laptop to get for this use and what kind of modem will he need for thedifferent hookups? Someone told him he could get a cellular modem. Is this correct. Since we are fairly new to computers, the more basic the explanation the better. But the more information the better also Thank you for your time in this matter