Not garbled - lots of good information.

In regards to riding, what sort of terrain do you have to ride on? Is it mostly flat, rolling terrain? Any hills - length and average gradient you could get to and train on?

Nothing wrong with using the road bike and doing some road races to mix things up. But the tri bike leg is more about riding around a percentage of your FTP - so constant tempo rather than the pace changes occurring in a road race or crit. I would suggest variations of longer intervals would translate better e.g. 4*10, 2*20 min around your FTP. Before the power meter and not knowing about FTP, I found weekly hill repeats going at a solid effort up a local climb with around a 20 minutes duration (with gradients around 4-5%) was a great way of getting more even power in the legs. I find it easier to hold a higher power effort whilst climbing and also as it’s very noticeable to feel if you start slacking off to keep pushing.

Also if using average speed as a metric (many variables that don’t make using this ideal) - during your rides try and hold the average speed you want to end up racing at for a duration of the training ride. Then start increasing time at that speed gradually as your training progresses. If you can’t hold a shorter distance at the speed you want to race at, you won’t be able to do that for the whole bike leg in a race! Training only slow teaches you to race slow!

*Don’t discount recovery rides though. Not every session should be hard…

If otherwise not injured, you feel your running is stronger than your bike leg? Best gains are always made focussing on your weakest leg. If it is the bike then you need to focus your attention here.

Swimming sounds like your strength so I'd continue what you are doing training wise, just like you say next time be up front and enjoy the ride just following some fast feet. The reasons are two fold - it's faster sitting on fast feet and also less need to constantly sight buoys as usually the faster guys know what they are doing and keep on course.