You would really be much better trying to stay at hotels that offer wireless internet access... I'm rolling out wireless broadband to some hotels/coffee shops etc... so there are ones that offer the service.

Alternatively, check to see if the hotel has an analogue phone port so you can use dial-up... it's not ideal... but will probably work out better/cheaper than the 3g option.

Or.... if you are really lucky...depending on where you are... some hotels are cat5e/cat6 cabled up.. so you may be able to plug in a network cable in your room...

best to approach the bigger chains to see what they offer..and just try and wangle it so you stay in the relevant hotels...