Welcome to Siege

Some great advice in this thread, so I will keep my comment limited mostly to EJ info.
As has been mentioned, EJ is nice for making alts to assist your main character. And of course, Broadsword is happy to sell you Soul Stones to make your main character more versatile.
EJ crafters are great for keeping yourself supplied with and repairing your own gear and perhaps a few to sell - but beyond that, they are the most limited template in the EJ program. They cannot use com deeds, stacks of materials cannot exceed what they can actually hold before banking it (and will not combine with a stack already in the bank), they cannot mount a beetle that is storing items, and they cannot access supplies in a house. They can only get 1 BOD per day, cannot bribe any of them, and cannot use BOD books. All of that is perfectly fine if you only use your crafter to meet your basic needs (after all, EJ is just a trial size sample of UO). In your case I would suggest using your primary account for your crafter, since that is the playstyle you prefer the most. Invest in a few Soul Stones eventually, and the same character can then be used for higher end content. Your main account prolly also has High Seas and other upgrades already. On the note of fishing - do not leave your ship at sea on Siege Perilous.
On the other hand, EJ have almost no limits on skills, equipment, quests and dungeons, etc. They do not get Power Scroll drops or EM drops, but just about everything else is fair game. (Make sure your paid account is the one that throws things in the trash, for example, as EJ can earn but NOT redeem cleanup points.) At some point tho, you will be wanting a PvMer so you can get materials such as barbed leather for your crafter.
Your one character can have a house on Siege and your home shard at the same time. Recall, sacred journey, and the travel function on Vendor Search maps do not work on Siege, so put some thought into the location of that house if you decide to set up a shop. Keep in mind that Siege is full of fairly self-sufficient souls so your wares may not sell as swiftly as other shards. Imbued suits are always in demand, though. Specially this time of year!
Most importantly - just have fun!