Not sure how accurate these sticker weights are anyway as these rigs tend to be heavier than stated especially in the toyhauler category. You can go online and check weights of similar sized toyhaulers or just go and have it weighed locally. It looks like your 18' TH would fall into the 1/2 ton TV category in most cases so just about any full-size truck would do the job.
Take it to the scales and weigh it. I am on my third toy hauler, and none of them were as light as the manufacturer and stickers said they were. Generally, the stickers in or on the trailer are the weights without options.