Yeah it was a wild ride. There’s really no best altitude to fly in the mountains, since no two situations are the same. You have to adapt to the cards you’ve been dealt.
If the weather is clear and winds are light, and you can afford to climb 1000 feet over the highest ridges, then that should keep you out of the bumps. Often though that isn’t possible, either because the terrain is too high and you don’t have the performance needed or oxygen, or more often because the weather won’t allow it.
General rule of thumb is that if you need you fly through the mountains and there is significant wind, then stick to the windward side of the valleys and avoid the leeward sides (lots of mechanical turbulence and downdrafts as the wind spills over ridges). If there’s no wind, then stick to the sunny side of the valley, where you’re more likely to encounter rising air. Generally air will rise on that side and descend on the shadowed side.
The weather in real mountains though can change in a heartbeat, and often the best course is staying on the ground and waiting for better conditions.