I'm glad to hear I've been of assistance without even realising it
The Stagecoach West Megarider will cover a HUGE area, if you haven't already seen the validity area I would have a look. For example, it will cover you to Cirencester with a simple change in Cheltenham, which is a nice looking town that I need to actually stop off and explore one day. Cricklade is also a valid option, and I was surprised yesterday to see, when looking at my cycling maps, that Kemble is within 5 miles of Cirencester.
The main reason why I mention that area though is the Cotswolds Water Park. Also accessible on the same bus route from Cheltenham, and a place I really need to explore properly. I've been past many times on the bus but never actually into it. Despite it kind of sounding like a theme park, it's an outdoor leisure area full of options for walkers, cyclists, boating and more. Strongly worth researching, I've had a quick look at the area yesterday and I was determined to make a visit there one day. I'd have gone years ago, but I was not even slightly interested in physical health back then, whereas these days I can't spend enough time outside exercising and exploring!
I realise some of my suggestions here do involve a lot of time on buses, but in my mind it's worth it. Here's some more ideas, and I was going to do this via PM but as it could be useful to others I'll leave it publicly viewable:
- If you do the trip to Chepstow, you would be well placed to do the Wye Valley Greenway. Opened this spring, it follows the old railway route to Tintern. I would *strongly* recommend checking bus times if you go both ways by bus however, as the 24 is not very frequent. Still worth doing in one direction or the other mind, and the Stagecoach Buses app will be incredibly handy. I'm going to do a trip report on the Wye Valley Greenway later today, as the weather is not great enough to go out for a bike ride today

For now though, the big draw for me was Tidenham Tunnel. I've uploaded a walkthrough video of it to YouTube, no fancy editing or anything, as I have no idea what I'm doing or anything with that kind of thing. Still, for the easiest way to experience the tunnel at home, this video will do just that:
- A trip that involves buses Gloucester-Cheltenham-Swindon-Avebury, so a long day, but Avebury has its own version of Stonehouse which might be of interest. Staying on the same bus to Devizes (the route ends in Trowbridge) will give you a rather nice little town which would be worth a couple of hours exploring.
- A more local to Gloucester day now, take the 64 to Stonehouse. It takes an indirect route, but I like Stonehouse. A nice little place, and Standish is not far away. I haven't looked into it myself, but Standish is almost right next to the mainline between Birmingham and Bristol, so you'd get GWR IETs as well as 158s, 165s, 166s, Voyagers and XC HSTs. A linesiding photography idea I need to research myself. Anyway, not the point of this day trip! National Cycle Network's Route 45 between Stonehouse and Nailsworth is all on a traffic-free section, around 5 miles at the most. I did this one the other week, after the honourable
@Kite159 told me of it. Very easy going, virtually no gradients to speak of, and Nailsworth looked like a nice place to stop off for a coffee. I had had a long journey of around 3 hours to get there, and I was determined to get on with the walk so didn't stop to investigate. It can also be accessed from Stroud, and not too far from the town centre. That is also accessed off the 64, but more directly off the 63.
- You might have noticed I've got plenty of ideas here! Another day out would involve the buses to Ross on Wye (a town local to me but never properly explored, embarrassingly as there's so many walks to do from there) and over to Monmouth. Another area with boatloads of walking opportunities, a town worth exploring properly and that is on my list to do myself. I visited a few weeks ago on a cycle tour, if I hadn't had the long and challenging mission back to Hereford ahead of me (the A466 is seriously evil...) and a social bike ride to lead that afternoon I'd have stopped for longer. The 34 from Ross is much quicker, the 35 is far slower but would take on more scenery.
- More walking options in Gloucestershire, and one on my list to do still, is the Gloucester & Sharpness Canal. It's quite long, I think 16 miles each way, so not one to try and do in one day. There is somewhere the bus from Stonehouse serves near Slimbridge that is alongside the canal, but without looking it up I can't remember where that is. I need to do this one myself, as I want to see Sharpness. Nothing hugely exciting there, but it is at the end of a former railway and I am pretty sure it used to host a ferry crossing many years ago. I just fancy seeing what's actually there! Slimbridge has a RSPB site, by the way, if that is of interest. The canal is easily accessed from Gloucester Quays, a short walk from the city centre.
I think that's all the ideas I have to share for now!