Most cas fans would give their 12 fingers to have a slightly lucky comeback win to take a major trophjy

Personally, I'd see the league leader's shield as a massive success this season. Not many clubs have won any SL trophy, whether that be the LLS or the grand final.
What happens after that is often in the lap of the Gods. Any of the top four should be able to beat each other, and it will come down to who performs over 80 minutes of a play-off and then who performs in the grand final.
One thing is for sure - any club would trade Cas' place in the league at the moment.

Obviously as you're top. However, I doubt any of Leeds, Hull or Salford would swap their season as a whole so far for yours since they're all still in the top four and in the cup semi finals.

Can you explain why it was a lucky win at Wembley?

What was lucky was the way Hull gift d you 2 tries in the first half.

I went to Wheldon Road last night exp citing to see this Cas side which is sweeping all before them play some of expansive, off the cuff rugby. Instead I saw the opposition stifle the, from playing their normal game.

Hull have the measure of Cas. Cas may have won, but Hull have found the way to competing and beating Cas.

Maybe not, but that depends on your perspective.
I'd rather win the LLS than lose in a cup semi or in the cup final.
Only one of the four teams left in the cup will win it.
There are only three trophies available per year. Cas have a firm grasp on one of them, whereas the clubs still in the cup have a 25% (roughly!) chance of winning it.
I'd rather be eight points (+ a massive points difference) ahead in the league than in the semi-final of the cup.

Maybe not, but that depends on your perspective.
I'd rather win the LLS than lose in a cup semi or in the cup final.
Only one of the four teams left in the cup will win it.
There are only three trophies available per year. Cas have a firm grasp on one of them, whereas the clubs still in the cup have a 25% (roughly!) chance of winning it.
I'd rather be eight points (+ a massive points difference) ahead in the league than in the semi-final of the cup.

But you'd also presumably rather win the cup than the LLS, especially if you were still in the top four like Hull, Leeds and Salford likely will be? LLS is nice to win but doesn't really count for too much unless you win the grand final, ask any Warrington fans whether they considered 2016 a successful season. I'd also probably rather get to Wembley and lose than win the LLS (but I'd maybe think differently if Wakefield had got there 3 years ago like Cas rather than a 40 year drought).

Winning the LLS, in terms of going on to win the GF can be a poisoned chalice, just ask the Huddersfield team of a few seasons ago.
The winning mentality that some FC fans are going on about, doesn't yet apply to Hull.
Leeds have this in abundance, as do Wigan (although they look to be too far away to mount any serious challenge) and for this reason, I think that Leeds may well win the GF.
They dont seem to be playing any spectacular stuff at the moment but, they do keep on winning and when it gets to the serious part of the season, they know how to prepare, both physically and more importantly, mentally.
Cas may prove me wrong but, it's a really tough ask to win the GF at the first attempt, unless it happens to be two "new" clubs in there.

Leeds could win it but I'd be surprised if they won if the grand final was between them and Cas. They might have a better winning mentality and more experience but not enough to bridge the gap in quality between their team and Cas. Also, Leeds might have more experience of winning big games but Cas have beat them about seven times on the trot so I think it probably balances out in the psychological stakes.

I fear you're somewhat overstating things to suggest there's a gap in quality between the two sides. Cas are playing much better at the moment, no doubt about it, but aside from a quality half and the league's best fullback I think you'd struggle to make a convincing argument for the individual superiority of any of your side over their Leeds counterparts. You're playing great stuff right now. We're not rough right now. A lot can happen between now and September.

For most of the season it's been asked do Cas have a plan B because it's not always possible to play the free flowing rugby we've enjoyed. I think the last few weeks have shown, yes, we do. Quite rightly Leeds then Hull fancied their chances on the back of the disappointing cup defeat. It wasn't pretty, the ref has been blamed, it's been gritty but at the end of the day Cas have toughed it out on both occasions and got the 2 points. I think that shows we might be able to tough out a victory in knockout rugby (and yes I'm well aware we didn't in the cup).

Re: The LLS. At the start of the season a friend asked if I'd be disappointed if we didn't anything. The answer was yes. Now it looks like the LLS is in our back pocket, if we didn't add to it I'd be slightly disappointed. For me it would be a minor disappointment not a major one - I was one of 37 Cas fans who saw us lose at Widnes the second time we were relegated, I've seen club record defeats, Thursday night trips to Whitehaven, home cup defeat to Barrow. So yes, I'd love us to win the GF but I'd just be happy to see us win a trophy for the first time while I've been watching them.

Finally...if and it's a big if we reach Old Trafford, I'd fancy our chances against Salford and against Leeds, the latter who we've had the edge over since the 2014 cup final. A GF against Hull would be tough to call, both teams have the edge over the other on home turf so neutral territory would be interesting. The only team I'd not fancy playing is Wigan.

Looking forward to the rest of the season regardless.

Yes, without a doubt.
But I wouldn't swap our current position with anyone. I'd much rather be where we are in the leagues and out of the cup than in 2nd-4th position and in the cup semi-final.
Winning the LLS would be a massive achievement for a club without silverware for decades. It might not count as much as the GF, but it's more than most clubs will achieve this season.

There's a fair few reasons why Cas shouldn't win anything barring the LLS.
Mind, I'd have to dig fairly deep in the barrel to find them. They're showing few signs of running out of steam even if the early season style has dropped a notch.

I don't support Cas.