I usually try to get the younger child's lessons out of the way first, and then set them up with a activity while I teach the older child, then bring them both together for a activity related to the lesson.
With just a two year split, think of the subjects that can be done together. Science and social studies are two that can be done together. With the remaining subjects, what are your expectations? Do you need to sit with each of them during it all? I have made folders in the past for my kids that have things for them to work on that shouldn't need my help. Sometimes it is a worksheet (word search for spelling words or something else), sometimes it refers to another source (like a slip of paper will say do page 39 of your workbook), etc. I would put that folder, with their journal, and anything else needed, on the table. When I worked with one child, the other would work through their folder.
I've heard the workbox system can work really well for teaching with more than one child.
My suggestion would be to do as much as possible together as a family, likely not at the kitchen table. Provide engaging experiences, project opportunities, activities, and let each child take from it what he or she is ready for. If you want structure, by all means, block it in. Target the ability level of the elder child for the most part: you'll be amazed at how much the younger one absorbs. Things that have worked very well for us:
Nature hikes. Photo-documentation, identification, use of field guides.
Gardening projects, even just on the kitchen windowsill.
Watching documentaries. There are so many great nature documentaries available these days.
Read-alouds... fiction, historical fiction, science, history.
Field trips to historical places.
Geocaching. Even a smartphone is a sufficient tool for this. Great fun for families.
Cooking and baking. Meal-planning and preparation.
Textile handiwork (sewing, knitting, needle- and wet-felting)
Science "experiments" in the kitchen and around the home
Art projects ("Discovering Great Artists" by Kohl and Solga was a great resource)
Listening to music, attending concerts, the Classical Kids music history series of story & music CDs
Home-maintenance chores and home-improvement skills (laundry, cleaning, painting, yardwork, etc.)
This sort of stuff will cover about 90% of the learning you'd want kids to get at this age. My kids learned reading and basic math without structured programs, experiential learning like the above helping them along with those areas naturally. But even if you felt you needed structured programming for those things, you'd probably find it would take very little time with all the other bases covered together.
My kids have been unschooled, so any bookwork they did was motivated by their own desires. Even from quite young ages they tended to gravitate to such things together, meaning that the eldest would sit down with her math, and then two younger siblings would get all keen on doing the same sort of thing. They never seemed to have a problem with staying on-task. I would circulate from child to child offering help as needed. It was pretty easy and pretty efficient. So I guess I'd say that nurturing high levels of self-motivation (avoiding coercion, finding enticing, engaging materials, etc.) is extremely helpful.
Mountain mama to three great kids and one great grown-up
With my children, we do science and history as a group.The older two are expected to do their own assignments without me helping them too much and I take turns working with the younger two.
Midwife (CPM, LDM) and homeschooling mama to:
13yo ds 10yo dd 8yo ds and 6yo ds and 1yo ds