Hi, I'm a single adopter, six years in.
The key to this is planning, and accepting that it may be a few years before you are in a positon to adopt.
Firstly why are you assuming that a local job will be low paid?. I also had to find a local job, which was actually higher paid than the job where I travelled regionally, because I went from the voluntary to the public sector.
I was quite mercenary in my approach, I knew a civil service job would give the best pay, best terms and conditions including flexible working, holidays, part time and pension and adoption leave. So thats what I targeted, took me 18 months to find it but I got there. Its much easier to get a full time well paid job, and then ask to go part time after adoption leave, than is to find a well paid part time job.
Don't worry about university fees, its too far in the future and not a given for a any child, and particularly adoptive children, But who knows what the education system will look like in 20 years time.
Kids don't need foreign holidays. We have been lucky enough to have three in 6 years, one was at the end of our first year so I still had some savings, one was for my 50th birthday and one last year which I saved for 18 months for. The next few years will be uk only, we stay will friends or in Youth hostels, or premier inn if we are pushing the boat out. One of the highlights of our year is our annual trip to Cornwall. My son also loves north Wales.
Activities - well my son is quite busy, but two clubs are after school so free, a £10 a month membership at the local gym gives him unlimited swimming, ( swimming lessons about £45 a half term) scouts is £3 a week, tennis lessons are £20 a month. so not too bad. Most art galleries, musuems and libraries have lots of free activities. Investing in things like English Heritage memberships gets you lots of 'free' days out.
In terms of finances what you need to focus on your housing and living costs and childcare. Childcare is the killer to be honest. Its one of, though far from the only, reason why I adopted a school age child. When he was at primary I worked four short days, so no childcare costs apart from £5 a week for two afterschool clubs. Childcare in the school holidays can be anything from £60 to £100 a week. A nursery or childminder will be expensive.
The other killer is affording adoption leave, most agencies will be looking for you to have at least 6 months off, if not a year.
You don't have to be rich to adopt, just financially stable, and be able to afford the essential costs.
You would probably qualify for child benefit, its not masses but £80 a month will keep them in shoes ( children's shoes are flipping expensive) or pay a bill. You may qualify for tax credits. Your child may qualify for DLA if they have extra needs.
Do a budget, some of your costs will not change eg mortgage, up your utilities and food a bit etc. Think about what you can strip out, I 'saved' lots of money because of course I didnt go out for 18 months. Try to get to a reasonable idea of what you need to live on, rather than what you would like to live on. That should help target job search.
I'm very fortunate, I do get an adoption allowance, but because I didnt include it in my financial planning, we are quite comfortable, but I could manage without it.
As a singly the other major issue they will focus on is your support network, so you need to think carefully about that