Coming from where we are the travel is always an issue, our season in N Premier was arguably easier than this season, which is brutal, with monster 3 hour trips every other week (the only 2 'local' games are Durham and Consett which are still a good shank)
Any of the 3 teams mentioned could make the step up, the difference is not that great. We felt we were just coming to terms with things when Covid struck and we all know what happened next.
You need either a massive, interchangeable squad, or the ability to 'aquire' new players when needed. The standard of rugby isn't that much higher, but all the games are attritional and unless you're very lucky, injuries will happen. If you can't replace these injuries with similar quality, you WILL be punished. Teams in the NP are much more efficient too, particularly away from home, many don't seem to play much rugby but make far fewer errors than we see in N1E and grind out results.
It's a step up, but not a massive one. All 3 teams mentioned 'could' have a good go if promoted, but as Pock found out a few years back, if you go up and then actually lose players, it's impossible. Being big and strong and able to 'bully' teams in N1E doesn't work either, as there's bigger, better, more experienced bullies 1 up, so careful thought needs to go into what happens...do you stick with the lads who've got you up, or do you pi55 them all off by recruiting 'better' players? This can obviously backfire in spectacular fashion in the long run as there's no guarantee it works anyway.
Money does seem to talk quite a lot too as some teams are rich and flying one season, only for a mass exodus to occur if the £ dries up or more is offered elsewhere. 2 or 3 cases spring to mind immediately.
For us it was definitely worthwhile as we cracked on with the same team, having the experience of playing a division up, and with no £ involved our end there's no real issue no matter what happens. We played some good stuff and were able to compete with most teams. However, if we'd stayed up and had the crippling injury list we had at the start of this season we'd have been getting pumped heavily every week. 'If' you invest to go up, and are desperate to stay up..... be in for the long haul!
Driff and Ilkley know what to expect, Heath are an ambitious outfit and fair play if they get there. All could do well, all could come straight back down...it's that fine a line.