I've been trying/eliminating a lot of different tools lately. I wanted to take notes on the subject, might as well post for others to see/learn from as well.
The Day Tripper Easel: I love it. If you order one, you will not regret it. You'll need a good tripod.
The reason I like it is that it's light. I will post some of my proposed improvements below. I may customize it a great deal and post what I've changed. I've been thinking about asking Josh Been if I can recreate it as carbon Fiber, but I want to wait until I've made all my changes first.
Tripod for the easel: I've tried all the cheap ones, and then a few pricey ones. The one I love is "k&f concept tripod 62" DSLR"
The reason this is a good one for me is that it fits in my bag. Everything fits in my medium size back pack. I have everything in the bag, and I have room for other things, like art books, water bottles, bug spray, sun screen, etc.
Pens: The drawing is an important step and I'm trying not to skip this step, ever. But the reason it's critical is to record the shadows at the start. The sun moves so fast, and a drawing is a good way to record your values. It also lets you compose not only the location of objects, the scale of them relative to the others, but also the values overall.
The Prismacolor pens cool grey (double ended) are great. If you get the 10%, 30%, 50%, 70%, and black, you'll be all set. I went with all gradients and find that I really don't want to be that gradient. I'd rather have the contrast be more prominent.
I've also ordered a blending pen to help smooth out some of the lines.
Paints: I use Oil, but water soluble, because some of the big festivals do not allow turps. I've tried many, and Duo Aqua is by far the best.
Brushes: I have not found a good go-to set of brushes. It depends on my mood so far. I need more time to play with all the brushes in all the different circumstances before I can give good advice here. But so far, the synthetic high end brushes seem to be what I lean toward.
Medium: I'm not sure if I'm going to use mediums moving forward. If my paints are moving well, like they do with the Duo Aqua, then I think I'll try to go without mediums. Everything I've been using has been changing the transparency and drying too quickly. That includes Medium-W and Gamblin Neo-Megilp. I liked the Neo-Megilp more, because it's gel consistency keeps it from sliding down the palette.
There is so much more on this topic, not the least of which is:
The uprights that hold the panel/canvas do not fit lengthwise in my backpack. I would rather not have the upright be so long. It could be half the length. I'm thinking of using tent-pole type methods to allow it to fit. If it could fold up it could essentially hold a larger painting and fit into the bag better. It's possible a tent-pole or kite type solution could allow for a full working easel without a separate tripod. I'll keep thinking this through and will post diagrams if anything comes of it.
It would also be nice if it could hold my brushes as they get paint on them. Having a quick way to set those into a spot would be great.
Finally The swing hooks that hold onto the tripod should also close shut the top. When the top is closed there's nothing to hold it shut, except the string, which I don't go through the trouble of. It would be easier to just shut those swing hooks and know that they are holding the top lids shut.