ready for my first trip (?)

i just took this old boy 150km across the netherlands in 2 days. it honestly went surprisingly well, so i'm a lot more confident about my upcoming plans to bike down to germany next month, and eventually try to make it down to spain.

the bike used to be my dad's and it was in his shed for like 15 years, but aside from the gears being a little flaky (they work but don't correspond properly with my handling them), i think i've patched it up pretty well. (new tires, brakes, mudguards, all oiled up. oh and it's on its 4th saddle now, not in the picture). i was thinking of getting a new(er) (non-mountain)bike for the big trip but since it held up for this part i'm willing to see how far it'll take me. i'm pretty comfortable on it by now.

it was a whole hassle getting a carrier for the back, unfortunately it's very high up but it was the only solution. i'm happy with my bag and i think my camping gear will go on the other side, but i think i'm probably gonna need more stuff. my front fork has no bolt things to attach anything to, do you guys think it'll work to fashion something out of tie wraps? or would it be better to get a steer or frame bag? i'm not a big fan of weight on my steer but i see so many people do it on here.

any (tight budget) tips? should i look into fixing the gears before i hit any hills?