If you plan on wearing it then yes you need to train with it on. Hard or soft armor. In the sand box we wore our full kits to go the range. If you are training for a gun fight then you need to wear what you have for that gun fight in training
They have the sleds on ebay for $36. Type in weight sled and they come up. My pick some up and get my kids to pull them while i shoot at them.(sleds, not the kids)