It costs a lot to recruit and administer volunteers , if you volunteer at a hospital there is a lot of training you have to do for example, which costs and that you have to do so you understand all the policies . If the role is one that needs doing every weekday not just it's a nice extra, the hospital needs to know you can make a commitment, they do get that there will be times when you are away, or unwell, so on top of not being regular you will also be away occasionally because of stuff like that. And so far away I'm not surprised that unless you have a rare skill they would be reluctant to pay the extra expenses. 10 miles @ 50 p a mile each way would be a tenner, at 28 miles away that would be an extra 14 quid, you'd get free parking plus probably a token meal voucher if you were there the whole day.
There is an amazing range of volunteer roles, in an event to present long service awards to volunteers I was sitting next to lady who had volunteered for 30 years helping people who needed help to learn about camouflage make up, for people who needed help, eg because they had vitiligo.
It's got to be the right role for the organisation and for you.
If you can do bookkeeping or accounts there are many organisations that need a treasurer, most of this could be done in your own time, if you were a trustee you would need to commit to some meetings as well. We don't know what you talents are and what sort of volunteering you. But as someone who has volunteered for years and been involved with the administration of volunteers I know a bit about it
There are always adhoc volunteering opportunities, for example locally the rotary club is after volunteers to do a stunt on their Santa sledge at the local supermarket. There are a lot of drop instructions locally and they can always have an extra volunteer for.making tea or washing up. Local historical.or.family history societies often have indexing and transcription projects which again can be done in your own time. Our community bus operates on volunteer drivers and administrators.
Register with your local volunteer services in your own town, the fact that you are willing to travel may mean there is a wider range of places you could go than someone who is reliant on the bus after 9.30