@Steves thanks for reaching out! Unlike BikeFlights, who specializes in the shipping of bikes, we don't have any insider tips on shipping options for camping equipment specifically. Maybe our community has some ideas?
At REI, we believe a life outdoors is a life well lived.
I sent a ~60lb box of tools earlier this year from CA to NM. I got a large Costco Tote to pack them all in. Cost about $80-$90...sent on Friday arrived on Tuesday as I recall. You have to take packages that size into a Post Office.
With the Post Office you can send it General Delivery to a Post Office and pick it up from there...I think you need have to give a 2 week window or something...they won't keep it forever...but they will forward it on to another Post Office if you can't pick it up. This is done a lot by thru hikers for resupply and bounce boxes.
You can also send a package via UPS up to 150# also with size limitations. I think the prices are similar but for some reason I found it less convenient or more limited or something.