Not being rude, but she would have a hard job being 26 weeks and due end of October! I'm 26 weeks this week and due end of November. Unless baby is being brought very early?
Only reason I raise this is if you are thinking of getting something for her, say a spa day, there will come a point where she can't really do anything/much in a spa, so may be tricky for her to use. After baby comes, finding time to do a spa will be tricky in the first couple of months.
If she's actually 30 weeks on, chances are she will have already started using some form of support if she needs it.
Baby carriers are a VERY personal choice , and whilst it's a really lovely gift idea, I would encourage her to try some first before buying her one! If you wanted to get her a carrier though, I would recommend a close caboo which can generally be used straight away for a newborn, and then you tend to find the type that works for you for later on.
For me - first time round, all I got were gifts for baby, and not to sound ungrateful, it would have been lovely to have something for me! A home pampering hamper would have been lovely, or a hamper after birth full of all the delicious things that I couldn't eat during pregnancy. A friend received a gift of a pregnancy photo shoot which she loved - I would have hated this, but everyone is different.
Honestly though, I would just sound her out first - find out (subtly) what she has / doesn't have already (a lot of first time mums seem to be super organised... second timers not so much!).
The PP suggestion of a hamper of lovely teas, chocolate etc sounds lovely - the last trimester is tough going!