I picked the Riverlands Farm first time around as well. It turned out that I loved fishing, so it was lots of fun…initially. But just like you, I felt I was running out of space. And so, partly because of space issues, in the Summer of Year 2, I started a new Standard Farm.
But now, with more experience, I’ve realised that none of the farms have too little space. Sure, the Riverlands Farm is a little more cramped than some other maps, but if you need more space, just move things off the farm and into other parts of Stardew Valley. For example:
Crops. One of the main reasons I restarted was that I couldn't plant a serious amount of crops and still have space for Fish Ponds, decoration and other things. Luckily 1.5 fixed this problem. The amount that you can fit on your
Ginger Island Farm is plenty big enough for most situations, especially when combined with your Greenhouse.
Processors. The Desert is a great place to put your processors. Just make sure that they are all in safe locations so that they don't get destroyed by Sandy and Emily on Fall 15.
This might help.
Tapped trees. If you clear out the Quarry you can plant trees to tap over there. Just put flooring everywhere so that rocks don't spawn and get in your way.
And if your animals are taking up too much space, know that they’re still very profitable even if you just feed them Hay.
This leaves you with a pretty much clean-sheet farm to design just the way you want. Now you can add in your favourite bits, and go from there! The Stardew Valley Planner is a huge help in this process, as is the Valley Showcase section of these forums.
And if don't want to go through all that effort, I'll say this: Stardew only gets better the second time.
Alternatively, you could take a break and play some other games, because they're fun as well!