Here is a list of what I will give you when you leave the Spawn Village:
1 Stone Sword
1 Saddle
1 Compass
1 Clock
Leather Armor (Full Set)
32 Carrots
56 Torches
And here is a list of what I will give you once you find where you want to build your castle:
1 Iron Pick
1 Diamond Shovel
1 Iron Axe
1 Iron Door
1 Coal Block
1 Lead
1 Bed
1 Bedrock Block
2 Chests
4 Levers
4 Signs
16 Oak Stairs
32 Iron Fences
32 Ladders
40 Emeralds (388)
64 Oak Planks (5)
200 Torches
576 Stone Slab Blocks (43)
768 Stone Brick Blocks (98) (12 stacks)
Here is a list of what I will provide either to you or for you:
Protection for your double chest
1 Beacon
2 Iron Golems (for you village)
9 Diamond Blocks (for the Beacon)
64 Wool of your color
Hopefully, this should be enough for you to build a basic castle and get started (This is what I built my castle with + some extras leftover).