You have a number of different options, from living alongside an other piggy or bonded pair to trying and bond him with a bought baby (keeping in mind that it may not work out and that need to have the space for a divided cage if that happens, i.e. a living alongside option as your fall-back plan B).
You could also consider having him neutered so he can live with a sow or two after the obligatory 6 weeks post-op safety wait. Many of my own string of adopted 'husboars' (i.e. neutered boars living with sows) have started out either as singles or as fallen out boys; one or two were even deemed as 'unbondable' - the worst bully boy actually ended up with 13 wives in his hey-day and lived the dream for 5 1/2 years of a 7 years' long life!
Please take your time explore the different options and see which one is most practicable for you, in your location and personal situation. What you ultimately do has to fit your situation and gives your boy the happiest life possible.
I have travelled on the train for over 2 hours each way to rescue date a boar with sows of mine; but I do have the advantage of having fairly good railway connections and a much more central location compared to you.
These guides explore your different options with their various pros and cons in greater depth so you can make as informed a decision as possible:
Single Guinea Pigs - Challenges and Responsibilities
A Comprehensive Guide to Guinea Pig Boars
Neutered / De-sexed Boars And Neutering Operations: Myths, Facts and Post-op Care
A Closer Look At Pairs (Boars - Sows - Mixed)