yes you are dealing with tough ages there :)
WHY do you need to entertain them constantly? pffft. Ask what they want to do, if they want to continue to camp, maybe bring a friend along but honestly, let them do what they want now. You can't invent fun all the time or entertain a kid 24/7.
I remember when younger I would say to Mom--I am bored and she would answer--THEN be bored. There are tons of things to do, choose or be bored :) :)
I let my 10 yr old daughter bring all her electronics and she loves them. we are out and about at the beach swimming, nature centers, tourist stuff, biking etc all day long---at night when she is super tired she does 'her thing' on what she likes, IPAD, phone, tablet etc. laid up in the toyhauler doing her own thing.....parents don't need to control 24/7 of each kids trip at all.
good luck on this tho cause this is the age when they are changing alot more and not our little darlings we can control and fascinate with saying, oh watch that squirrel or take this little bucket and fill it with pine cones LOL :) :)