I think it will be ok. DH and I WOH FT so our dog is left alone 9hr a day. Up until he was about 4yr we crated while we were at work. We definitely crate trained him as a puppy and that worked great. We have invisible fence so it's easy for him to hang out outside when we are home. We do travel a few times a year (usually shorter trips) and we have someone come dog sit at our house. Usually it's my mom but at Xmas time we went to WDW for a week and one of DH's single friends house/dog sat for us. My SIL and her husband travel a few times a year and they either kennel their dog or the woman who fostered him (he was a puppy when they got him from a lab rescue) will watch him. I think you'd be fine to come/go as you please. Dog will get used to the "routine" of it even if it isn't very routine. And if you crate him/her that'll just help. Dogs really seem to love their crates. The most important thing will be getting some type of daily exercise/activity and you can just fit that into your schedule. I would recommend basic puppy training class. We did that and found it helpful for getting "good manners" started right from the start. You could also try doggy daycare. This would give you a chance to get the dog exercised and socialized while you are going about your day and also most of the doggy daycare places do kenneling so then pup would already be used to and enjoy the environment if you used their kenneling service during your vacation travel.
We've had our dog for 8.5yr, have had 2 kids since, we work and have kids' activities, and we haven't regretted a day of it.
Mom to two amazing DDs ('07 & '09) and a fur baby.
Gluten free since Nov '11 after non-celiac gluten sensitive diagnosis. Have had great improvement or total elimination of: migraines, bloating/distention, heartburn, cystic acne, canker sores, bleeding gums, eczema on elbows, dry skin and scalp, muscle cramps, PMS, hair loss, heart palpitations, fatigue. I'm amazed.