You should be able to find surface copper veins a few blocks underneath bits of copper ore on the surface, it's a good idea to add map markers any time you find ore bits on the surface so you can come back later and dig up the vein underneath.
If you're using realistic climate distribution, try lowering the polar-equator distance, that will make how far you have to travel to get to colder/warmer climates significantly easier.
If you just want an "easy" experience with minimal challenge for finding resources with "interesting" world gen, try these settings:
World Height: 384 blocks
World Generation:
Climate Distribution: Realistic
Landcover: 50%
Landcover scale: 75%
Upheaval rate: 60%
Landform scale: 20%
Polar-Equator distance: 5000 blocks
Story structures distance scaling: 25%
Forestation & shrubs: +50%
Global deposit spawn rate: 200%
Surface copper deposit frequency: Very common
Surface tin deposit frequency: Very common
Do keep in mind that this won't provide the "intended" experience of the game, but it might be closer to the experience you're looking for. You might also want to enable colour accurate world map.
These settings should produce mountainous terrain with lakes and oceans being fairly common, and almost entirely remove the difficulty of locating certain resources, though for others you might still need to travel north or south; but the distance you'll need to travel is significantly less than with default worldgen settings.
Here's a breakdown of the settings so that you can adjust them yourself if wanted:
World Height - Changes how tall the world is, taller worlds allow for taller mountains
Climate Distribution - Changes between random patches and polar/north-south distribution of climate
Landcover & Landcover scale - Changes how large landmasses are and how much water there is between them
Upheaval rate - Adjusts commonness of hills/mountains
Landform scale - Adjusts the size of biomes/landforms
Polar-Equator distance - Changes the distance between poles when using realistic climate distribution, ie the distance between the hottest climate and coldest climates
Story structures distance scaling - Changes how far apart/away story/lore related structures generate
Forestation & shrubs - Changes the density of trees and shrubs
Global deposit spawn rate - Changes how common ores are
Surface deposit frequencies - Changes how common surface spawns of ores are