In the case of outdoor-only cats, I prefer to house sit, though I'm open to other solutions. 

Bears have one of the most powerful senses of smell, so it's important to have no lingering smells. If I can't house sit, I'll care for the cat at my home. Most other wildlife are nocturnal or dawn-and-dusk animals, and those aren't a concern if you have a noon feeding. But, for bears that are on the move in the day (not the typical dawn-and-dusk), you're in a "rock and a hard place" because there are no bear-proof feeders. 

But, if you have no other choice on short notice, use an automatic feeder and give a smaller quantity of food while you're away so that there are no leftovers. If you stick to a routine of once per day (noon avoids most wildlife with the exception of other outdoor cats), you'll have an easier time feeding when you're away.

A clean litter box discourages spraying. Self-cleaning litter boxes are available—I've never used one. But, it might be all you need if you're only gone for a few days. Test before you go on vacation! 

FYI, my outdoor/indoor cat refuses to use a litter box except during winter. Instead, she uses my decomposed granite sideyard for poop and mulched front yard for urine. Rascal! But, it's easy to clean (filter) and it leaves zero odor.

• Pet profiles—Provide a writeup for each pet, unique needs, personality, likes/dislikes and routine. 

• Medication and Vet—Provide written instructions for administering medication and vet contact info. Post this info on your refrigerator.

• Cleaning instructions & cleaning products—Leave deep cleaning instructions, including prioritized tasks, along with a list of approved products for specific use cases. I find mild soap and/or vinegar to be ideal in most cases. My homes have granite countertops and hardwood floors and tile. 

• Key Backup—Recommend a temporary keycode lockbox with a backup key just in case your pet caregiver gets locked out for any reason. 

• Security—If there are any known security vulnerabilities, let's brainstorm on a fix in advance of your vacation. For example, if your pet knows how to get out of a locked gate, consider inserting a carabiner into your gate lock to protect against this case and windy days.

• Fire prevention—Test your smoke alarms before you leave on vacation, especially if you don't have wired smoke alarms.

• Weatherization—Ensure that you've weatherized your swamp cooler if you plan to be away starting October 1st or pre-schedule weatherization with your provider, including blowing out your sprinklers and cleaning out your roof gutters.

• Emergency—Provide an emergency phone number of a local, reliable friend or family member that can fill in for me in the event that my family has an emergency. I too will provide you my husband's number just in case you can't reach me.

• Evacuation plans—Provide me your evacuation plan (for example, fire). Consider these guidelines. I'm very resourceful and will do my best to help if I'm able. I've completed FEMA's IS-10.a (Animals in Disasters: Awareness and Preparedness). I have a second property so if I need to rehome your household pets I can.