Just finished up my pre-need (that's service, coffin, vault and transportation), headstone, burial plot and escrow account for opening (that's a backhoe). Do it now: it's cheaper to negotiate these costs now and less burdensome to your family. Also, leave an always current inventory of wills, trusts, passwords, keys, assets and accounts where survivors can easily find them. Leave specific instructions for what you'd like done with social media accounts and decide whom gets what ahead-of-time. Finally, don't put any children on bank accounts, make it payable upon death. Prevent, as much as possible, squabbling about money and/or property should someone die or become incapacitated.
PS: opt-in as an organ donor, where applicable.