What's the lathe weigh, and how much of it can you fit in the back? Overload springs or airbags would be a huge help, but I once spent a week hauling in scrap metal about 1500# at a time in my 87 (3" Rancho & 31's.) Don't go too fast, think ahead, and try not to do any "panic maneouvres" and you should be fine. I'd stay off the freeway as well - no sense buying trouble when you get enough for free...
You should probably expect a little spring sag, tho, if you've a longish trip ahead of you. If that worries you, divide the load into trips of 500# or less, if possible.