Well for a child who can read fluently, I would let K be a year of reading to learn. There are thousands of educational, nonfiction childrens books available in a variety of subjects so my recommendation would be to dust off the library cards and to get some shelving in the home ready for a lot of library traffic.
Do you have an eReader that you're willing to stock with materials for him to read?
Are you equipped to print a lot of papers (text or worksheets) off of the internet?
If you want to purchase some programs for him then you need to first decide what you want to cover and whether its worth it to buy or borrow the materials. Check your libraries collection and check into inter library loan also because you can preview
a ton of home school materials that way, then you can order the ones that you like the best.
Some different programs that I like for English:
First Language Lessons For the Well-TrainedMind level 1Levels 1 and 2 are completely oral and can be done in K if you compact the program by doing a lesson each day and skipping when necessary instead of 2-3x a week. The value in this program is learning and memorizing a lot of core grammar points and learning to ID them in oral, written and aural language. There is no writing required and it can literally be done in 3-10 minutes a day, the program is very gentle and repetitive, but you can skip some things as needed.
To go along with FLL 1 and 2 I would get books from the
Brian P. Cleary (Words are CATegorical series of about 26 books, check your library for them)
Robin Pulliver (
Punctuation takes a Vacation, Silent Letters Loud and Clear, Nouns and Verbs have a Field Day, Happy Endings: A book about Suffixes, The Case of Incapacitated Capitals). That would be enough grammar for a Ker, just go through FLL and read a few of Clearies books on each part of speech, then just ID nouns and such in your reading time and viola, an excellent and easy grammar curriculum for a Ker.
For math, you can take a similar approach, find a math program that you like and read as many living math books as you want to go with it.
Mathematics Enhancement Program is free for the cost of printing. You can compact Reception (K) and Year 1 for an advanced K student. If you don't want to have to print then there are many other options and many publishers offer placement tests so that you can place your son at the appropriate level in their scope and sequence.
Check out LivingMath.net for booklists and ideas about how to enrich a math curriculum with picture books.
Science: If you have a PDF capable eReader than I strongly suggest you visit this
site. You can download PDF versions Science textbooks for 1st-6th grade and since your son is already reading so well, I'd just read through the textbooks together, discussing as you went along. Each book has grade level life science topics so you can read through the 1st grade book, then read about each topic at a higher level in the 2nd grade book, then read about the same topics at a higher level in the 3rd grade book. You can also download and print workbooks to go with the texts, but they aren't necessary but you will be able to pick and choose which pages your son might enjoy rather than printing the whole book. You can still supplement and enhance your sons science studies with projects if you want to (or not) or with library books, but reading and discussing from a series of texts can be a wonderful way to gain a large amount of background knowledge.
Geography: Get a good atlas and spend several minutes with it each day, play geography games on SheppardsSoftwares geography section. Evan Moor makes good geography workbooks that are easy to implement. You can also google "blobbing" to see if that is something you might be interested in.
There are only a very few "wrong" ways to do Kindergarten-2nd grade. So long as the student is learning to read, write and developing mathematically these should be very low pressure years for you and for him. Your son can already read so K should be the year that he learns knowledge by reading, drawing and playing his way through the school day.
I'm sure that you already have quite a collection of educational toys such as blocks, puzzles, games, but you might go through and see about purging unused games and puzzles and replacing them with more educational versions such as geopuzzles or getting more detailed wall maps/globes just so that you have those tools on hand.