I would also ask what the budget is ( or certainly if there is a budget concern), then what type of crawling you would want to do or what type of environment you will be crawling at!Some folk like to stay at one spot and crawl hard lines on rocks, others like to "crawl" what is on their local trail or even just take the truck for a walk and get it muddy.... Never simple these days asking questions!!!π€£
Bottom line there are 2 main different type of crawlers; A scale crawler - looks like a truck, and a Comp Crawler - looks like a tool designed for rock crawling! There are rigs that lie between these also.
But let us know the other queries and we can help π