Hi Julieann,
I have found some info which you may or may not have on your James Tweedie and Dorothy (Dorcas) nee Petelday Tweedie.
In the Dumfries and Galloway Family History Society publication "County of Dumfries Census Records of 1841 by surname - Lochmaben Landward" your James is listed as being 64 years old and working as an agricultural labourer living in a property at Upper Dormont (photos to follow). His wife, Dorcas (real name Dorothy) was also present aged 63. Also within the same household was their daughter Mary, aged 25, who had by then a 1 year old son called James.
Since I had a few spare credits left with scotlandspeople webiste (with time running out before they lapsed), I searched for your James' death certificate and struck gold.
James died on January 28th 1862 at 11pm of old age (with no immediate medical attendant present) at his home at the Smallholm Tollbar (a property that no longer exists today. Again, I can take pics for you of the site). He was the tollkeeper at the time of his death in 1862 with his wife, Dorothy present.
The attendant was a William Wilson - a neighbour (probably the farmer) who lived at Smallholmburn (which still runs as a farm today).
Dorothy, his wife died in 1865.
[I have downloaded the death certificate for James and can email you it if you provide my with your email address (send it via a private message) - Due to copywrite restrictions, I cannot post the certificate here].
The cemetery searches will have to wait until next year.
I hope the above information reaches you in good health, and that you enjoy a wonderful Christmas.
Best wishes,
Kojak