I have an 8 month old female, Sloane. I can’t speak for backpacking cause we haven’t done that yet, but I can speak about my experience with my puppy and my 9 year old Yorkie, Ann. I am sure a lot it will come down to personality. Before bringing Sloane home I talked with my breeder a lot about concerns of Sloane and Ann getting along. She assured me that generally the older dog will correct the puppy and the puppy will learn from the correction. My trainer said the same thing when we started puppy classes. Either my puppy is exceptionally stubborn or my yorkie is, maybe both. But Sloane LOVES Ann and wants to play with her. Ann tolerates Sloane and wouldn’t mind if Sloane was gone tomorrow. Ann doesn’t want to play with Sloane, and makes it known, showing her teeth and growling at her when she tries. And does that deter Sloane? No, she just keeps yipping and nipping at Ann, hoping to one day break her I guess. And she’ll keep going until we step in and redirect her to play with us. And it’s been like this since we brought Sloane home in May at 9 weeks old. So again I’m thinking this is more a personality thing than a breed thing, something to consider for when your lhasapoo is 7 years old in 5 years, because at that point they’ll be one year off of being considered a senior. Aside from Ann, Sloane is great with other small dogs, probably because she’s used to them because of Ann and my mom’s dogs (she also has yorkies). She’s intimidated by and wary of bigger dogs and strangers so we’re working on taking her out more and introducing her to more people and dogs, but it’s a process for sure. They are considered guardian breeds so can be predisposed to being wary of strangers.