Protein on the go

Hard boiled eggs. cheese cubes (best at room temp, no refrigeration required.) nut butter in individual cups to be scooped out with celery. Or packed into celery and put in little plastic bags.

Hummus? It's possible to grind chickpeas or black beans, bake them slightly salted and eat them like crackers. These both may be considered not paleo though because they are legumes. You could probably do the same thing with lentils though.

7-11 has a pack with 2 eggs, a slice of cheese and a packet of saltines. In emergency situations, for $1.49 you're loaded with protein (I toss the saltines). Look in the refrigerated snacks section.

As long as the wax is unbroken, Babybel cheeses do not have to be refrigerated.

You can find yogurt in most convenience stores and also drugstores like Walgreens.

You can get individual squeezy packets of peanut butter and almond butter at places like Whole Foods, and also http://www.amazon.com/exec/obidos/ASIN/B002ATEZOG/metafilter-20/ref=nosim/. I suppose you could squeeze them out onto apples or celery, but I usually just eat it right from the packet. There are also individual, shelf-stable servings of hummus, in http://www.ivillage.com/sabra-hummus-singles-healthy-packaged-snacks-kids/6-b-462233, http://www.foodservicedirect.com/product.cfm/p/1935088/Classic-Hummus-with-Pretzel.htm?gclid=CjwKEAjwsdafBRC2rYuDuYXk2TESJACsUN_uqAjr-ZL4o1yEJS5iSnZyE3P8PpAbPTaFGmHpYRcwXxoC29fw_wcB, and http://www.amazon.com/exec/obidos/ASIN/B001HTG624/metafilter-20/ref=nosim/ formats. The first two links provided for illustration only--I've found them at Costco, grocery stores, and even some convenience stores. Oh, and most of the little fresh food shops in major airports have them, too. Amazon is the best place for the squeezy tubes. I'm also curious about easy to find snack foods (at convenience stores or fast food restaurants) Most convenience stores and drugstores in my area have a little section with sandwiches and other grab-n-go foods, and they usually have one- or two-packs of peeled hard boiled eggs, as well as egg salad sandwiches that are often not awful. They also have a couple shelves in the drink coolers for refrigerated dairy convenience foods, including blocks of cheese and string cheese. The convenience stores with little delis hidden inside often have deviled eggs, as well.

If you are in a city, in an area with a lot of offices, look for the places that serve them lunch -- many have pre-cut pre-wrapped little blocks of cheeses, bags of nuts, boiled eggs, hummus, and stuff that goes with them (not sure what the parameters of 'paleo' are, though). PB2, a powdered, fat-removed peanut butter thing, is easy to store and has a decent amount of protein. I really like eating the chocolate PB2 plain.

Starbucks sells roasted nuts by the cash register. They also have snack plates of fruit/cheese, and another with a hard-boiled egg, peanut butter, etc.

Dry-roasted edamame. I just buy it at the grocery store - it's everywhere. I also eat roasted soynuts. (Are these paleo? How strict are you about eating paleo?If you're a vegetarian, I imagine you eat legumes). Yogurt is fine unrefrigerated for quite a while. Not for days and days, but it can handle a day in a backpack. (Is dairy okay? If it's not, I think coconut milk yogurt should be fine, but it's way more expensive and only available specialty stores like Whole Foods. Tasty, though). Clif does make energy gels, but they're basically gooey Gatorade and not what you're looking for. Honestly, as much as I don't like Starbucks, they reliably have nuts and other pre-packaged healthy snacks.