Congratulations on joining the RV community. However, I feel that you have not allowed yourselves enough time to both sightsee and be back in 10 days. First I'm guessing that you'll need a day to recover from your flight and to inspect your new RV to make sure that all systems work. Then to provision it, at least with the basics before you leave the dealership or previous owner. You didn't say what you are buying but if it's either a Clas A, C or B, will depend on how far you can safely drive each day. We've always had Clas A's 36 feet down to now 30 feet, and back in my youth 😄 19 years ago when we got our first coach driving 400+ miles a day wore me out. Thus 300 to 350 miles a day was not as debilitating. Then when you stop for the night there's the setup which could take as much as an hour.
So for example it's 825 miles from Portland to Sequoia National Park which is 2 days just to get there. From there to home in Holden Beach is 2706 miles, so assuming 400 miles a day not taking in construction, accidents that stop traffic, etc, that's about 7 days of steady driving, so you've used up 10+ days.
I'm not trying to rain on your parade, but it's a big country. I'd suggest getting home directly to stay within your 10 day window, then spend time learning about your RV with short trips and then when you can take a month to go see those Redwoods.
And if I'm out of line in your opinion, I apologize in advance.
Have fun RVing.
