No. You can only have treasure trail rewards by doing clue scrolls only. (Clue scroll is a good way to have fun and make money. And if your are lucky, you might get 3rd age armor!)
No Treasure Trail is for F2P.
Not if you do not have a clue scroll, no.
Jellies or Avianes
Depending on the treasure trail(puzzle).
Depending on the treasure trail(puzzle).
You cannot plume helmets in runescape. But you can use a full helmet with a herald stand in your Player Owned House, and there are treasure trail rewards with different coloured plumes.
Trimmed amulets can not be created by players. They are from Treasure Trails in the members part of Runescape. To start a treasure trail you need to get a clue scroll. These are dropped by almost every monster in runescape. I reccommend Jellies (78) to get level 3 clue scrolls, Guards (28) to get level 2 clue scrolls and Men and Women (3) to get level 1 clues.
All trimmed armour are treasure trail rewards. You cant buy them anywhere else. You can buy it either from a person or G.E.
There are many, many possible clue scrolls, too many to list here. See the related links for several RuneScape fansites that have full Clue Scroll/Treasure Trail guides.
Timmy Time - 2009 Timmy's Treasure Trail is rated/received certificates of: Australia:G
Have Gun - Will Travel - 1957 Treasure Trail - 2.19 was released on: USA: 24 January 1959
Outlaw Trail The Treasure of Butch Cassidy - 2006 is rated/received certificates of: Singapore:PG USA:PG