Aerostitch makes vegan motorcycle gloves, they have 2 different pairs. One summer and one spring/summer/autumn. I have both pairs and really like them. You might want to go up a size if you order them.
http://www.aerostich.com/clothing/glove ... vegan.htmlFor boots I have a pair of TCX. Cant find them on their site now but boots usually have a really good declaration of what they are made of. Basically, the more racing-inspired boot, the more vegan options. This also goes for the MX side of motorcycling. If you are planning on cruising on your pre-war Harley you might find it a bit difficult to find suitable boots

Jackets and trousers are easy but check a couple of extra times since bikers apparently need to have some leather put somewhere on their clothes.
Helmets shouldnt be any problem unless you go for one of the retro-style ones which usually have leather lining.
Also, take out the foam back protection in the jacket you buy, throw it away and buy a real back protection.
BUT the thing is, if you want to be safe you shouldnt even think about getting on a motorcycle. They are stupid, dangerous, unsafe and good for nothing. Just be aware of the dangers, that is involved. You are very, very unprotected. If you accept the risks it is however very funny and a pretty sure way of getting speeding tickets/revoked license.
Regarding the "only driving on sunny happy country-roads"-idea. Do you already have a license? Otherwise I would guess that you will have to ride in the not so pleasant part of traffic before getting it. Its also oretty good to know how to handle those situations before you get into them. Because sooner or later you are going to find yourself on a highway heading into a city centre and nowhere else to go.
But all in all I would very much recommend it, the best is if one or more of your mates also ride or find a group that you can tag along with since riding alone can get a bit boring.