I agree that ultimately what is the oldest living thing comes down to a question of semantics. A distinction that's often made is clonal versus non-clonal organisms. I've seen Methuselah called the oldest non-clonal organism. The creosote bush that you mention is a clonal organism, as is Pando, a clonal colony of aspen thought to be something like 80,000 years old.
Remember, though, that the mass itself is not really the important part. The question is what is the surface gravity. Using your assumption of identical density (maybe not likely, but I don't know offhand what density is likely), the mass of this new planet in terms of the density rho will be M = rho*4/3*pi*R^3. The gravitational acceleration at the surface will be
a = (G M) / R^2
Combining that with the expression for the mass gives
a = G*rho*4/3*pi*R^3 / R^2 = (G*rho*4/3*pi) R.
All the stuff inside the parenthesis is assumed to be the same for both planets, so if we want to write it in terms of the surface gravity of Earth, g, and radius of Earth, r, then we'd have
a = g*(R/r). Thus, the surface gravity (under the assumption of identical density) is only 2.4 times greater.
Of course, if you're going to visit this place and plan to leave again (maybe not so useful without warp drive, given) then you might also be concerned with the energetic depth of the gravity well. For an object of mass m to escape to interstellar space from the surface will require an amount of energy
E = G*M*m/R
and in terms of the earth value E_earth this would be
E = (E_earth)*(R/r)^2
meaning it will take about 6 times as much energy as getting off Earth.
I was actually just thinking about this issue the other day while playing Mass Effect, because I was wondering if they'd done their numbers right on the planet properties (they had).
My girlfriend and I both read and liked the comic, and we were both pretty happy with the movie. We went with a couple of friends who had not read the comic but actually were the ones who suggested seeing the movie. They really did not like it. From talking to them, the problem seemed to basically be one of unfulfilled expectations. They knew it was a movie about superheroes and were expecting a typical superhero movie, which is to say an action-packed movie with pretty light themes. What they got was something that was dark and more dialog and ennui than action, so they were not happy.
Maybe if they'd been expecting something different going in they would have liked it better or perhaps not. Maybe there were other people who it would have suited better, but they decided not to see it assuming it was just another dumb superhero movie. I don't know, but I wouldn't discount the effect of mistaken expectations.
On the eighth day, God created FORTRAN.