>>91161 (OP)
>Diaper
Should be the simplest bit. Make sure you and your little understand each others limits and make house rules that put how much of an importance the diapers are. You set the rules in regards to bathroom usage and changes since you'll more than likely deal with them. Have fun finding outfits to put them in regards to looking cute and diaper access.
>Public
Go to places like Build-a-Bear and have fun making a plushie if they're into plushies. Have some time at the park and/or a Lake/Beach if possible. You could do theme parks too but as someone who has done that with their caretaker you're gonna want to look into bathrooms that are single and lockable if you want to change as needed.
Honestly most things you can do with diaper play in regards to stuff at home is pretty simple. Watch some movies they might enjoy, you can set the age rating if you so please, or dress them up in any way you like which would more than likely be the sissy stuff so dresses and the like. There isn't anything grand behind ideas with a Little to be honest. Just do things like a Daddy/Mommy would do with their toddler to keep them entertained and generally that will work.