Hi sparrowhawkms
Firstly, I shouldn't rely on trims to maintain aircraft heading - there's all sorts of things that can influence the flight path. Use the joystick, that's what it's for.
1. The SE5a is my favourite aircraft and I fly it a lot. It may take a while getting used to the guages but they can be used for flying by, no problem.
There are a couple of ways of navigating:
via a printed map and the compass + looking for landmarks (roads, rivers, railways etc.) or by pressing 'M' whilst in-flight. This gives you a very basic map. Pressing 'M' again will make it disappear.
2. I've found that, with practice, all aircraft can be flown using the in-cockpit guages. If you fly a particular aircraft a lot then you get used to it ( just like real life).
3. You can drag the hud guages anywhere you want to - you can even select which ones you want.
Don't forget, this is a simulator and not a game. It's hard because that's how it was in the day.
I hope you persist with it and come to enjoy it as much as we all do. It takes a lot of practice but you will soon be able to look over the side and know roughly where you are. Those HUD guages will disappear too