I too insure my trailer for $7500. Going rate these days.
State Farm called a boat dealer to ask how much replacement cost is of my 'ski boat' since they didn't believe $62k for any ski boat out there. Dealer said $70k
State Farm is expensive but I know where my agent lives and he fights for me when my stuff breaks and cuts a check on the spot. $600/yr if asking for 500k all around on $500 deductible.
My previous coverage was $480/yr, but it was like pulling teeth when my car got hit.